Merge branch 'SCons:master' into fix_py_3_9_resourceWarnings

32 files changed, 649 insertions, 706 deletions

diff --git a/SCons/CacheDir.py b/SCons/CacheDir.py
index 8be6643..14e52ad 100644
--- a/SCons/CacheDir.py
+++ b/SCons/CacheDir.py
@@ -125,7 +125,7 @@ def CachePushFunc(target, source, env):
         # In any case, inability to push a file to cache doesn't affect
         # the correctness of the build, so just print a warning.
         msg = errfmt % (str(t), cachefile)
-        cd.CacheDebug(errfmt, str(t), cachefile)
+        cd.CacheDebug(errfmt + '\n', str(t), cachefile)
         SCons.Warnings.warn(SCons.Warnings.CacheWriteErrorWarning, msg)
 
 CachePush = SCons.Action.Action(CachePushFunc, None)
diff --git a/SCons/Tool/jar.py b/SCons/Tool/jar.py
index a19c40a..ae44ff3 100644
--- a/SCons/Tool/jar.py
+++ b/SCons/Tool/jar.py
@@ -29,15 +29,19 @@ selection method.
 """
 
 import os
+from typing import List
 
+import SCons.Node
+import SCons.Node.FS
 import SCons.Subst
+import SCons.Tool
 import SCons.Util
 import SCons.Warnings
 from SCons.Node.FS import _my_normcase
 from SCons.Tool.JavaCommon import get_java_install_dirs
 
 
-def jarSources(target, source, env, for_signature):
+def jarSources(target, source, env, for_signature) -> List[str]:
     """Only include sources that are not a manifest file."""
     try:
         env['JARCHDIR']
@@ -51,21 +55,22 @@ def jarSources(target, source, env, for_signature):
     result = []
     for src in source:
         contents = src.get_text_contents()
-        if not contents.startswith("Manifest-Version"):
-            if jarchdir_set:
-                _chdir = jarchdir
-            else:
-                try:
-                    _chdir = src.attributes.java_classdir
-                except AttributeError:
-                    _chdir = None
-            if _chdir:
-                # If we are changing the dir with -C, then sources should
-                # be relative to that directory.
-                src = SCons.Subst.Literal(src.get_path(_chdir))
-                result.append('-C')
-                result.append(_chdir)
-            result.append(src)
+        if contents.startswith("Manifest-Version"):
+            continue
+        if jarchdir_set:
+            _chdir = jarchdir
+        else:
+            try:
+                _chdir = src.attributes.java_classdir
+            except AttributeError:
+                _chdir = None
+        if _chdir:
+            # If we are changing the dir with -C, then sources should
+            # be relative to that directory.
+            src = SCons.Subst.Literal(src.get_path(_chdir))
+            result.append('-C')
+            result.append(_chdir)
+        result.append(src)
     return result
 
 def jarManifest(target, source, env, for_signature):
@@ -76,7 +81,7 @@ def jarManifest(target, source, env, for_signature):
             return src
     return ''
 
-def jarFlags(target, source, env, for_signature):
+def jarFlags(target, source, env, for_signature) -> str:
     """If we have a manifest, make sure that the 'm'
     flag is specified."""
     jarflags = env.subst('$JARFLAGS', target=target, source=source)
@@ -88,11 +93,14 @@ def jarFlags(target, source, env, for_signature):
             break
     return jarflags
 
-def Jar(env, target = None, source = [], *args, **kw):
-    """
-    A pseudo-Builder wrapper around the separate Jar sources{File,Dir}
-    Builders.
+def Jar(env, target=None, source=[], *args, **kw):
+    """The Jar Builder.
+
+    This is a pseudo-Builder wrapper around the separate jar builders
+    depending on whether the sources are a file list or a directory.
     """
+    # TODO: W1113: Keyword argument before variable positional arguments list in the definition of Jar function
+    # TODO: W0102: Dangerous default value [] as argument
 
     # jar target should not be a list so assume they passed
     # no target and want implicit target to be made and the arg
@@ -105,14 +113,14 @@ def Jar(env, target = None, source = [], *args, **kw):
         source = target
         target = None
 
-    # mutiple targets pass so build each target the same from the
+    # mutiple targets passed so build each target the same from the
     # same source
     #TODO Maybe this should only be done once, and the result copied
     #     for each target since it should result in the same?
     if SCons.Util.is_List(target) and SCons.Util.is_List(source):
         jars = []
         for single_target in target:
-            jars += env.Jar( target = single_target, source = source, *args, **kw)
+            jars += env.Jar(target=single_target, source=source, *args, **kw)
         return jars
 
     # they passed no target so make a target implicitly
@@ -121,6 +129,7 @@ def Jar(env, target = None, source = [], *args, **kw):
             # make target from the first source file
             target = os.path.splitext(str(source[0]))[0] + env.subst('$JARSUFFIX')
         except:
+            # TODO: W0702: No exception type(s) specified
             # something strange is happening but attempt anyways
             SCons.Warnings.warn(
                 SCons.Warnings.SConsWarning,
@@ -143,68 +152,68 @@ def Jar(env, target = None, source = [], *args, **kw):
     # if its already a class file then it can be used as a
     # source for jar, otherwise turn it into a class file then
     # return the source
-    def file_to_class(s):
-        if _my_normcase(str(s)).endswith(java_suffix):
-            return env.JavaClassFile(source = s, *args, **kw)
-        else:
-            return [env.fs.File(s)]
+    def file_to_class(src):
+        if _my_normcase(str(src)).endswith(java_suffix):
+            return env.JavaClassFile(source=src, *args, **kw)
+        return [env.fs.File(src)]
 
     # function for calling the JavaClassDir builder if a directory is
     # passed as a source to Jar builder. The JavaClassDir builder will
-    # return an empty list if there were not target classes built from
+    # return an empty list if there were no target classes built from
     # the directory, in this case assume the user wanted the directory
     # copied into the jar as is (it contains other files such as
-    # resources or class files compiled from proir commands)
+    # resources or class files compiled from prior commands)
     # TODO: investigate the expexcted behavior for directories that
     #       have mixed content, such as Java files along side other files
     #       files.
-    def dir_to_class(s):
-        dir_targets = env.JavaClassDir(source = s, *args, **kw)
+    def dir_to_class(src):
+        dir_targets = env.JavaClassDir(source=src, *args, **kw)
         if dir_targets == []:
             # no classes files could be built from the source dir
             # so pass the dir as is.
-            return [env.fs.Dir(s)]
-        else:
-            return dir_targets
+            return [env.fs.Dir(src)]
+        return dir_targets
 
     # loop through the sources and handle each accordingly
     # the goal here is to get all the source files into a class
     # file or a directory that contains class files
-    for s in SCons.Util.flatten(source):
-        s = env.subst(s)
-        if isinstance(s, SCons.Node.FS.Base):
-            if isinstance(s, SCons.Node.FS.File):
+    for src in SCons.Util.flatten(source):
+        src = env.subst(src)
+        if isinstance(src, SCons.Node.FS.Base):
+            if isinstance(src, SCons.Node.FS.File):
                 # found a file so make sure its a class file
-                target_nodes.extend(file_to_class(s))
+                target_nodes.extend(file_to_class(src))
             else:
                 # found a dir so get the class files out of it
-                target_nodes.extend(dir_to_class(s))
+                target_nodes.extend(dir_to_class(src))
         else:
             try:
                 # source is string try to convert it to file
-                target_nodes.extend(file_to_class(env.fs.File(s)))
+                target_nodes.extend(file_to_class(env.fs.File(src)))
                 continue
             except:
+                # TODO: W0702: No exception type(s) specified
                 pass
 
             try:
                 # source is string try to covnert it to dir
-                target_nodes.extend(dir_to_class(env.fs.Dir(s)))
+                target_nodes.extend(dir_to_class(env.fs.Dir(src)))
                 continue
             except:
+                # TODO: W0702: No exception type(s) specified
                 pass
 
             SCons.Warnings.warn(
                 SCons.Warnings.SConsWarning,
-                ("File: " + str(s)
+                ("File: " + str(src)
                 + " could not be identified as File or Directory, skipping.")
             )
 
-    # at this point all our sources have been converted to classes or directories of class
-    # so pass it to the Jar builder
-    return env.JarFile(target = target, source = target_nodes, *args, **kw)
+    # at this point all our sources have been converted to classes or
+    # directories of class so pass it to the Jar builder
+    return env.JarFile(target=target, source=target_nodes, *args, **kw)
 
-def generate(env):
+def generate(env) -> None:
     """Add Builders and construction variables for jar to an Environment."""
     SCons.Tool.CreateJarBuilder(env)
 
@@ -222,14 +231,14 @@ def generate(env):
             jar_bin_dir = os.path.dirname(jar)
             env.AppendENVPath('PATH', jar_bin_dir)
 
-    env['JAR']        = 'jar'
-    env['JARFLAGS']   = SCons.Util.CLVar('cf')
-    env['_JARFLAGS']  = jarFlags
+    env['JAR'] = 'jar'
+    env['JARFLAGS'] = SCons.Util.CLVar('cf')
+    env['_JARFLAGS'] = jarFlags
     env['_JARMANIFEST'] = jarManifest
     env['_JARSOURCES'] = jarSources
-    env['_JARCOM']    = '$JAR $_JARFLAGS $TARGET $_JARMANIFEST $_JARSOURCES'
-    env['JARCOM']     = "${TEMPFILE('$_JARCOM','$JARCOMSTR')}"
-    env['JARSUFFIX']  = '.jar'
+    env['_JARCOM'] = '$JAR $_JARFLAGS $TARGET $_JARMANIFEST $_JARSOURCES'
+    env['JARCOM'] = "${TEMPFILE('$_JARCOM','$JARCOMSTR')}"
+    env['JARSUFFIX'] = '.jar'
 
 def exists(env):
     # As reported by Jan Nijtmans in issue #2730, the simple
@@ -238,7 +247,7 @@ def exists(env):
     # stop trying to detect an executable (analogous to the
     # javac Builder).
     # TODO: Come up with a proper detect() routine...and enable it.
-    return 1
+    return True
 
 # Local Variables:
 # tab-width:4
diff --git a/test/AS/fixture/myas.py b/test/AS/fixture/myas.py
index 3d05c79..a348ace 100644
--- a/test/AS/fixture/myas.py
+++ b/test/AS/fixture/myas.py
@@ -1,6 +1,7 @@
 import sys
 
-if sys.platform == 'win32':
+
+def my_win32_as():
     args = sys.argv[1:]
     inf = None
     while args:
@@ -10,29 +11,41 @@ if sys.platform == 'win32':
             args = args[2:]
             continue
         args = args[1:]
-        if not a[0] in "/-":
+        if not a[0] in '/-':
             if not inf:
                 inf = a
             continue
-        if a[:3] == '/Fo': out = a[3:]
+        if a[:3] == '/Fo':
+            out = a[3:]
+
     with open(inf, 'rb') as ifp, open(out, 'wb') as ofp:
-        for l in ifp.readlines():
-            if l[:3] != b'#as':
-                ofp.write(l)
-    sys.exit(0)
+        for line in ifp:
+            if not line.startswith(b'#as'):
+                ofp.write(line)
+
 
-else:
+def my_as():
     import getopt
+
     try:
         opts, args = getopt.getopt(sys.argv[1:], 'co:')
     except getopt.GetoptError:
         # we may be called with --version, just quit if so
         sys.exit(0)
     for opt, arg in opts:
-        if opt == '-o': out = arg
+        if opt == '-o':
+            out = arg
+
     if args:
         with open(args[0], 'rb') as ifp, open(out, 'wb') as ofp:
-            for l in ifp.readlines():
-                if l[:3] != b'#as':
-                    ofp.write(l)
+            for line in ifp:
+                if not line.startswith(b'#as'):
+                    ofp.write(line)
+
+
+if __name__ == "__main__":
+    if sys.platform == 'win32':
+        my_win32_as()
+    else:
+        my_as()
     sys.exit(0)
diff --git a/test/AS/fixture/myas_args.py b/test/AS/fixture/myas_args.py
index 24d68dc..7a5e6fa 100644
--- a/test/AS/fixture/myas_args.py
+++ b/test/AS/fixture/myas_args.py
@@ -1,6 +1,7 @@
 import sys
 
-if sys.platform == 'win32':
+
+def my_win32_as():
     args = sys.argv[1:]
     inf = None
     optstring = ''
@@ -21,25 +22,38 @@ if sys.platform == 'win32':
             out = a[3:]
             continue
         optstring = optstring + ' ' + a
+
     with open(inf, 'rb') as ifp, open(out, 'wb') as ofp:
-        ofp.write(bytearray(optstring + "\n",'utf-8'))
-        for l in ifp.readlines():
-            if l[:3] != b'#as':
-                ofp.write(l)
-    sys.exit(0)
-else:
+        optstring = optstring + "\n"
+        ofp.write(optstring.encode('utf-8'))
+        for line in ifp:
+            if not line.startswith(b'#as'):
+                ofp.write(line)
+
+
+def my_as():
     import getopt
+
     opts, args = getopt.getopt(sys.argv[1:], 'co:x')
     optstring = ''
 
     for opt, arg in opts:
-        if opt == '-o': out = arg
-        else: optstring = optstring + ' ' + opt
+        if opt == '-o':
+            out = arg
+        else:
+            optstring = optstring + ' ' + opt
 
     with open(args[0], 'rb') as ifp, open(out, 'wb') as ofp:
-        ofp.write(bytearray(optstring + "\n",'utf-8'))
-        for l in ifp.readlines():
-            if l[:3] != b'#as':
-                ofp.write(l)
+        optstring = optstring + "\n"
+        ofp.write(optstring.encode('utf-8'))
+        for line in ifp:
+            if not line.startswith(b'#as'):
+                ofp.write(line)
+
 
+if __name__ == "__main__":
+    if sys.platform == 'win32':
+        my_win32_as()
+    else:
+        my_as()
     sys.exit(0)
diff --git a/test/CC/CC-fixture/.exclude_tests b/test/CC/CC-fixture/.exclude_tests
new file mode 100644
index 0000000..3f2bc0f
--- /dev/null
+++ b/test/CC/CC-fixture/.exclude_tests
@@ -0,0 +1 @@
+mycc.py
diff --git a/test/CC/CC-fixture/mycc.py b/test/CC/CC-fixture/mycc.py
new file mode 100644
index 0000000..eb11c87
--- /dev/null
+++ b/test/CC/CC-fixture/mycc.py
@@ -0,0 +1,55 @@
+"""
+Phony cc command for testing SCons.
+
+Copies its source file to the target file, dropping lines that match
+a pattern, so we can recognize the tool has made a modification.
+Intended for use as the $CXX construction variable.
+
+Note: mycc.py differs from the general fixture file mycompile.py
+in arg handling: that one is intended for use as a *COM consvar,
+where no compiler consvars will be passed on, this one is intended
+for use as $CC, where arguments like -o come into play.
+"""
+import getopt
+import sys
+
+def fake_win32_cc():
+    args = sys.argv[1:]
+    inf = None
+    while args:
+        arg = args[0]
+        if arg == '-o':
+            out = args[1]
+            args = args[2:]
+            continue
+        args = args[1:]
+        if arg[0] not in '/-':
+            if not inf:
+                inf = arg
+            continue
+        if arg.startswith('/Fo'):
+            out = arg[3:]
+
+    with open(inf, 'rb') as infile, open(out, 'wb') as outfile:
+        for line in infile:
+            if not line.startswith(b'/*cc*/'):
+                outfile.write(line)
+
+def fake_cc():
+    opts, args = getopt.getopt(sys.argv[1:], 'co:')
+    for opt, arg in opts:
+        if opt == '-o':
+            out = arg
+
+    with open(args[0], 'rb') as infile, open(out, 'wb') as outfile:
+        for line in infile:
+            if not line.startswith(b'/*cc*/'):
+                outfile.write(line)
+
+if __name__ == '__main__':
+    print(f"DEBUG: {sys.argv[0]}: {sys.argv[1:]}")
+    if sys.platform == 'win32':
+        fake_win32_cc()
+    else:
+        fake_cc()
+    sys.exit(0)
diff --git a/test/CC/CC-fixture/test1.c b/test/CC/CC-fixture/test1.c
index 7535b0a..6748e2c 100644
--- a/test/CC/CC-fixture/test1.c
+++ b/test/CC/CC-fixture/test1.c
@@ -1,3 +1,3 @@
 This is a .c file.
 /*cc*/
-/*link*/
+#link
diff --git a/test/CC/CC-fixture/test2.C b/test/CC/CC-fixture/test2.C
index a1ee9e3..388133b 100644
--- a/test/CC/CC-fixture/test2.C
+++ b/test/CC/CC-fixture/test2.C
@@ -1,3 +1,3 @@
 This is a .C file.
 /*cc*/
-/*link*/
+#link
diff --git a/test/CC/CC.py b/test/CC/CC.py
index 6363273..a548421 100644
--- a/test/CC/CC.py
+++ b/test/CC/CC.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,106 +22,29 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os
 import sys
 import TestSCons
 
 _python_ = TestSCons._python_
-_exe   = TestSCons._exe
+_exe = TestSCons._exe
 
 test = TestSCons.TestSCons()
 
 test.dir_fixture('CC-fixture')
-
-if sys.platform == 'win32':
-
-    test.write('mylink.py', r"""
-import sys
-args = sys.argv[1:]
-while args:
-    a = args[0]
-    if a == '-o':
-        out = args[1]
-        args = args[2:]
-        continue
-    if not a[0] in '/-':
-        break
-    args = args[1:]
-    if a[:5].lower() == '/out:': out = a[5:]
-infile = open(args[0], 'rb')
-outfile = open(out, 'wb')
-for l in infile.readlines():
-    if l[:8] != b'/*link*/':
-        outfile.write(l)
-sys.exit(0)
-""")
-
-    test.write('mycc.py', r"""
-import sys
-args = sys.argv[1:]
-inf = None
-while args:
-    a = args[0]
-    if a == '-o':
-        out = args[1]
-        args = args[2:]
-        continue
-    args = args[1:]
-    if not a[0] in '-/':
-        if not inf:
-            inf = a
-        continue
-    if a[:3] == '/Fo': out = a[3:]
-infile = open(inf, 'rb')
-outfile = open(out, 'wb')
-for l in infile.readlines():
-    if l[:6] != b'/*cc*/':
-        outfile.write(l)
-sys.exit(0)
-""")
-
-else:
-
-    test.write('mylink.py', r"""
-import getopt
-import sys
-opts, args = getopt.getopt(sys.argv[1:], 'o:')
-for opt, arg in opts:
-    if opt == '-o': out = arg
-infile = open(args[0], 'rb')
-outfile = open(out, 'wb')
-for l in infile.readlines():
-    if l[:8] != b'/*link*/':
-        outfile.write(l)
-sys.exit(0)
-""")
-
-    test.write('mycc.py', r"""
-import getopt
-import sys
-opts, args = getopt.getopt(sys.argv[1:], 'co:')
-for opt, arg in opts:
-    if opt == '-o': out = arg
-infile = open(args[0], 'rb')
-outfile = open(out, 'wb')
-for l in infile.readlines():
-    if l[:6] != b'/*cc*/':
-        outfile.write(l)
-sys.exit(0)
-""")
+test.file_fixture('mylink.py')
 
 test.write('SConstruct', """
 cc = Environment().Dictionary('CC')
-env = Environment(LINK = r'%(_python_)s mylink.py',
-                  LINKFLAGS = [],
-                  CC = r'%(_python_)s mycc.py',
-                  CXX = cc,
-                  CXXFLAGS = [])
-env.Program(target = 'test1', source = 'test1.c')
+env = Environment(
+    LINK=r'%(_python_)s mylink.py',
+    LINKFLAGS=[],
+    CC=r'%(_python_)s mycc.py',
+    CXX=cc,
+    CXXFLAGS=[],
+)
+env.Program(target='test1', source='test1.c')
 """ % locals())
 
 test.run(arguments = '.', stderr = None)
@@ -130,10 +55,12 @@ if os.path.normcase('.c') == os.path.normcase('.C'):
 
     test.write('SConstruct', """
 cc = Environment().Dictionary('CC')
-env = Environment(LINK = r'%(_python_)s mylink.py',
-                  CC = r'%(_python_)s mycc.py',
-                  CXX = cc)
-env.Program(target = 'test2', source = 'test2.C')
+env = Environment(
+    LINK=r'%(_python_)s mylink.py',
+    CC=r'%(_python_)s mycc.py',
+    CXX=cc,
+)
+env.Program(target='test2', source='test2.C')
 """ % locals())
 
     test.run(arguments = '.', stderr = None)
@@ -144,9 +71,9 @@ test.file_fixture('wrapper.py')
 test.write('SConstruct', """
 foo = Environment()
 cc = foo.Dictionary('CC')
-bar = Environment(CC = r'%(_python_)s wrapper.py ' + cc)
-foo.Program(target = 'foo', source = 'foo.c')
-bar.Program(target = 'bar', source = 'bar.c')
+bar = Environment(CC=r'%(_python_)s wrapper.py ' + cc)
+foo.Program(target='foo', source='foo.c')
+bar.Program(target='bar', source='bar.c')
 """ % locals())
 
 test.run(arguments = 'foo' + _exe)
diff --git a/test/CFILESUFFIX.py b/test/CFILESUFFIX.py
index 0a62307..2d24e25 100644
--- a/test/CFILESUFFIX.py
+++ b/test/CFILESUFFIX.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,9 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 """
 Verify that we can set CFILESUFFIX to arbitrary values.
@@ -35,32 +34,19 @@ _python_ = TestSCons._python_
 
 test = TestSCons.TestSCons()
 
-test.write('mylex.py', """
-import getopt
-import sys
-if sys.platform == 'win32':
-    longopts = ['nounistd']
-else:
-    longopts = []
-cmd_opts, args = getopt.getopt(sys.argv[1:], 't', longopts)
-for a in args:
-    with open(a, 'rb') as f:
-        contents = f.read()
-    sys.stdout.write((contents.replace(b'LEX', b'mylex.py')).decode())
-sys.exit(0)
-""")
+test.file_fixture('mylex.py')
 
 test.write('SConstruct', """
-env = Environment(LEX = r'%(_python_)s mylex.py', tools = ['lex'])
-env.CFile(target = 'foo', source = 'foo.l')
-env.Clone(CFILESUFFIX = '.xyz').CFile(target = 'bar', source = 'bar.l')
+env = Environment(LEX=r'%(_python_)s mylex.py', tools=['lex'])
+env.CFile(target='foo', source='foo.l')
+env.Clone(CFILESUFFIX='.xyz').CFile(target='bar', source='bar.l')
 
 # Make sure that calling a Tool on a construction environment *after*
 # we've set CFILESUFFIX doesn't overwrite the value.
-env2 = Environment(tools = [], CFILESUFFIX = '.env2')
+env2 = Environment(tools=[], CFILESUFFIX='.env2')
 env2.Tool('lex')
 env2['LEX'] = r'%(_python_)s mylex.py'
-env2.CFile(target = 'f3', source = 'f3.l')
+env2.CFile(target='f3', source='f3.l')
 """ % locals())
 
 input = r"""
diff --git a/test/CPPFLAGS.py b/test/CPPFLAGS.py
index 2808a53..ebae2df 100644
--- a/test/CPPFLAGS.py
+++ b/test/CPPFLAGS.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,9 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import sys
 
@@ -38,25 +37,22 @@ test = TestSCons.TestSCons()
 if sys.platform == 'win32':
     test.skip_test('Skipping on win32.\n')
 
-if sys.platform == 'win32':
-    test.file_fixture('mylink_win32.py', 'mylink.py')
-else:
-     test.file_fixture('mylink.py')
-
+test.file_fixture('mylink.py')
 test.file_fixture('mygcc.py')
 
-
 test.write('SConstruct', """
-env = Environment(CPPFLAGS = '-x',
-                  LINK = r'%(_python_)s mylink.py',
-                  LINKFLAGS = [],
-                  CC = r'%(_python_)s mygcc.py cc',
-                  CXX = r'%(_python_)s mygcc.py c++',
-                  CXXFLAGS = [],
-                  FORTRAN = r'%(_python_)s mygcc.py g77',
-                  OBJSUFFIX = '.obj',
-                  PROGSUFFIX = '.exe')
-env.Program(target = 'foo', source = Split('test1.c test2.cpp test3.F'))
+env = Environment(
+    CPPFLAGS='-x',
+    LINK=r'%(_python_)s mylink.py',
+    LINKFLAGS=[],
+    CC=r'%(_python_)s mygcc.py cc',
+    CXX=r'%(_python_)s mygcc.py c++',
+    CXXFLAGS=[],
+    FORTRAN=r'%(_python_)s mygcc.py g77',
+    OBJSUFFIX='.obj',
+    PROGSUFFIX='.exe',
+)
+env.Program(target='foo', source=Split('test1.c test2.cpp test3.F'))
 """ % locals())
 
 test.write('test1.c', r"""test1.c
@@ -86,19 +82,20 @@ else:
     test.must_match('mygcc.out', "cc\nc++\n")   
 
 test.write('SConstruct', """
-env = Environment(CPPFLAGS = '-x',
-                  SHLINK = r'%(_python_)s mylink.py',
-                  SHLINKFLAGS = [],
-                  CC = r'%(_python_)s mygcc.py cc',
-                  CXX = r'%(_python_)s mygcc.py c++',
-                  CXXFLAGS = [],
-                  FORTRAN = r'%(_python_)s mygcc.py g77',
-                  OBJSUFFIX = '.obj',
-                  SHOBJPREFIX = '',
-                  SHOBJSUFFIX = '.shobj',
-                  PROGSUFFIX = '.exe')
-env.SharedLibrary(target = File('foo.bar'),
-                  source = Split('test1.c test2.cpp test3.F'))
+env = Environment(
+    CPPFLAGS='-x',
+    SHLINK=r'%(_python_)s mylink.py',
+    SHLINKFLAGS=[],
+    CC=r'%(_python_)s mygcc.py cc',
+    CXX=r'%(_python_)s mygcc.py c++',
+    CXXFLAGS=[],
+    FORTRAN=r'%(_python_)s mygcc.py g77',
+    OBJSUFFIX='.obj',
+    SHOBJPREFIX='',
+    SHOBJSUFFIX='.shobj',
+    PROGSUFFIX='.exe',
+)
+env.SharedLibrary(target=File('foo.bar'), source=Split('test1.c test2.cpp test3.F'))
 """ % locals())
 
 test.write('test1.c', r"""test1.c
diff --git a/test/CXX/CXX-fixture/.exclude_tests b/test/CXX/CXX-fixture/.exclude_tests
new file mode 100644
index 0000000..9e0e6ff
--- /dev/null
+++ b/test/CXX/CXX-fixture/.exclude_tests
@@ -0,0 +1 @@
+myc++.py
diff --git a/test/CXX/CXX-fixture/myc++.py b/test/CXX/CXX-fixture/myc++.py
new file mode 100644
index 0000000..d369f61
--- /dev/null
+++ b/test/CXX/CXX-fixture/myc++.py
@@ -0,0 +1,55 @@
+"""
+Phony c++ command for testing SCons.
+
+Copies its source file to the target file, dropping lines that match
+a pattern, so we can recognize the tool has made a modification.
+Intended for use as the $CXX construction variable.
+
+Note: mycxx.py differs from the general fixture file mycompile.py
+in arg handling: that one is intended for use as a *COM consvar,
+where no compiler consvars will be passed on, this one is intended
+for use as $CXX, where arguments like -o come into play.
+"""
+import getopt
+import sys
+
+def fake_win32_cxx():
+    args = sys.argv[1:]
+    inf = None
+    while args:
+        arg = args[0]
+        if arg == '-o':
+            out = args[1]
+            args = args[2:]
+            continue
+        args = args[1:]
+        if arg[0] not in '/-':
+            if not inf:
+                inf = arg
+            continue
+        if arg.startswith('/Fo'):
+            out = arg[3:]
+
+    with open(inf, 'rb') as infile, open(out, 'wb') as outfile:
+        for line in infile:
+            if not line.startswith(b'/*c++*/'):
+                outfile.write(line)
+
+def fake_cxx():
+    opts, args = getopt.getopt(sys.argv[1:], 'co:')
+    for opt, arg in opts:
+        if opt == '-o':
+            out = arg
+
+    with open(args[0], 'rb') as infile, open(out, 'wb') as outfile:
+        for line in infile:
+            if not line.startswith(b'/*c++*/'):
+                outfile.write(line)
+
+if __name__ == '__main__':
+    print(f"DEBUG: {sys.argv[0]}: {sys.argv[1:]}")
+    if sys.platform == 'win32':
+        fake_win32_cxx()
+    else:
+        fake_cxx()
+    sys.exit(0)
diff --git a/test/CXX/CXX.py b/test/CXX/CXX.py
index 4be4199..ad00b55 100644
--- a/test/CXX/CXX.py
+++ b/test/CXX/CXX.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,9 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import sys
 import TestSCons
@@ -32,120 +31,46 @@ _exe   = TestSCons._exe
 
 test = TestSCons.TestSCons()
 
-
-
-if sys.platform == 'win32':
-
-    test.write('mylink.py', r"""
-import sys
-args = sys.argv[1:]
-while args:
-    a = args[0]
-    if a == '-o':
-        out = args[1]
-        args = args[2:]
-        continue
-    if not a[0] in '/-':
-        break
-    args = args[1:]
-    if a[:5].lower() == '/out:': out = a[5:]
-infile = open(args[0], 'r')
-outfile = open(out, 'w')
-for l in infile.readlines():
-    if l[:8] != '/*link*/':
-        outfile.write(l)
-sys.exit(0)
-""")
-
-    test.write('myc++.py', r"""
-import sys
-args = sys.argv[1:]
-inf = None
-while args:
-    a = args[0]
-    if a == '-o':
-        out = args[1]
-        args = args[2:]
-        continue
-    args = args[1:]
-    if not a[0] in '/-':
-        if not inf:
-            inf = a
-        continue
-    if a[:3] == '/Fo': out = a[3:]
-infile = open(inf, 'r')
-outfile = open(out, 'w')
-for l in infile.readlines():
-    if l[:7] != '/*c++*/':
-        outfile.write(l)
-sys.exit(0)
-""")
-
-else:
-
-    test.write('mylink.py', r"""
-import getopt
-import sys
-opts, args = getopt.getopt(sys.argv[1:], 'o:')
-for opt, arg in opts:
-    if opt == '-o': out = arg
-infile = open(args[0], 'r')
-outfile = open(out, 'w')
-for l in infile.readlines():
-    if l[:8] != '/*link*/':
-        outfile.write(l)
-sys.exit(0)
-""")
-
-    test.write('myc++.py', r"""
-import getopt
-import sys
-opts, args = getopt.getopt(sys.argv[1:], 'co:')
-for opt, arg in opts:
-    if opt == '-o': out = arg
-infile = open(args[0], 'r')
-outfile = open(out, 'w')
-for l in infile.readlines():
-    if l[:7] != '/*c++*/':
-        outfile.write(l)
-sys.exit(0)
-""")
+test.file_fixture('mylink.py')
+test.dir_fixture('CXX-fixture')
 
 test.write('SConstruct', """
-env = Environment(LINK = r'%(_python_)s mylink.py',
-                  LINKFLAGS = [],
-                  CXX = r'%(_python_)s myc++.py',
-                  CXXFLAGS = [])
-env.Program(target = 'test1', source = 'test1.cc')
-env.Program(target = 'test2', source = 'test2.cpp')
-env.Program(target = 'test3', source = 'test3.cxx')
-env.Program(target = 'test4', source = 'test4.c++')
-env.Program(target = 'test5', source = 'test5.C++')
+env = Environment(
+    LINK=r'%(_python_)s mylink.py',
+    LINKFLAGS=[],
+    CXX=r'%(_python_)s myc++.py',
+    CXXFLAGS=[],
+)
+env.Program(target='test1', source='test1.cc')
+env.Program(target='test2', source='test2.cpp')
+env.Program(target='test3', source='test3.cxx')
+env.Program(target='test4', source='test4.c++')
+env.Program(target='test5', source='test5.C++')
 """ % locals())
 
 test.write('test1.cc', r"""This is a .cc file.
 /*c++*/
-/*link*/
+#link
 """)
 
 test.write('test2.cpp', r"""This is a .cpp file.
 /*c++*/
-/*link*/
+#link
 """)
 
 test.write('test3.cxx', r"""This is a .cxx file.
 /*c++*/
-/*link*/
+#link
 """)
 
 test.write('test4.c++', r"""This is a .c++ file.
 /*c++*/
-/*link*/
+#link
 """)
 
 test.write('test5.C++', r"""This is a .C++ file.
 /*c++*/
-/*link*/
+#link
 """)
 
 test.run(arguments = '.', stderr = None)
@@ -161,35 +86,32 @@ test.must_match('test4' + _exe, "This is a .c++ file.\n", mode='r')
 test.must_match('test5' + _exe, "This is a .C++ file.\n", mode='r')
 
 if TestSCons.case_sensitive_suffixes('.c', '.C'):
-
     test.write('SConstruct', """
-env = Environment(LINK = r'%(_python_)s mylink.py',
-                  LINKFLAGS = [],
-                  CXX = r'%(_python_)s myc++.py',
-                  CXXFLAGS = [])
-env.Program(target = 'test6', source = 'test6.C')
+env = Environment(
+    LINK=r'%(_python_)s mylink.py',
+    LINKFLAGS=[],
+    CXX=r'%(_python_)s myc++.py',
+    CXXFLAGS=[],
+)
+env.Program(target='test6', source='test6.C')
 """ % locals())
 
     test.write('test6.C', r"""This is a .C file.
 /*c++*/
-/*link*/
+#link
 """)
 
     test.run(arguments = '.', stderr = None)
-
     test.must_match('test6' + _exe, "This is a .C file.\n", mode='r')
 
-
-
-
 test.file_fixture('wrapper.py')
 
 test.write('SConstruct', """
 foo = Environment()
 cxx = foo.Dictionary('CXX')
-bar = Environment(CXX = r'%(_python_)s wrapper.py ' + cxx)
-foo.Program(target = 'foo', source = 'foo.cxx')
-bar.Program(target = 'bar', source = 'bar.cxx')
+bar = Environment(CXX=r'%(_python_)s wrapper.py ' + cxx)
+foo.Program(target='foo', source='foo.cxx')
+bar.Program(target='bar', source='bar.cxx')
 """ % locals())
 
 test.write('foo.cxx', r"""
diff --git a/test/CXX/CXXFILESUFFIX.py b/test/CXX/CXXFILESUFFIX.py
index 0ae5827..1c55106 100644
--- a/test/CXX/CXXFILESUFFIX.py
+++ b/test/CXX/CXXFILESUFFIX.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,10 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
-
 
 import TestSCons
 
@@ -31,32 +29,19 @@ _python_ = TestSCons._python_
 
 test = TestSCons.TestSCons()
 
-test.write('mylex.py', """
-import getopt
-import sys
-if sys.platform == 'win32':
-    longopts = ['nounistd']
-else:
-    longopts = []
-cmd_opts, args = getopt.getopt(sys.argv[1:], 't', longopts)
-for a in args:
-    with open(a, 'r') as f:
-        contents = f.read()
-    sys.stdout.write(contents.replace('LEX', 'mylex.py'))
-sys.exit(0)
-""")
+test.file_fixture('mylex.py')
 
 test.write('SConstruct', """
-env = Environment(LEX = r'%(_python_)s mylex.py', tools = ['lex'])
-env.CXXFile(target = 'foo', source = 'foo.ll')
-env.Clone(CXXFILESUFFIX = '.xyz').CXXFile(target = 'bar', source = 'bar.ll')
+env = Environment(LEX=r'%(_python_)s mylex.py', tools=['lex'])
+env.CXXFile(target='foo', source='foo.ll')
+env.Clone(CXXFILESUFFIX='.xyz').CXXFile(target='bar', source='bar.ll')
 
 # Make sure that calling a Tool on a construction environment *after*
 # we've set CXXFILESUFFIX doesn't overwrite the value.
-env2 = Environment(tools = [], CXXFILESUFFIX = '.env2')
+env2 = Environment(tools=[], CXXFILESUFFIX='.env2')
 env2.Tool('lex')
 env2['LEX'] = r'%(_python_)s mylex.py'
-env2.CXXFile(target = 'f3', source = 'f3.ll')
+env2.CXXFile(target='f3', source='f3.ll')
 """ % locals())
 
 input = r"""
diff --git a/test/Java/JAR.py b/test/Java/JAR.py
index bc52a89..2d67717 100644
--- a/test/Java/JAR.py
+++ b/test/Java/JAR.py
@@ -23,6 +23,12 @@
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+"""
+Test Jar builder.
+
+These tests require a findable/working Java subsystem.
+"""
+
 import os
 import TestSCons
 
@@ -30,115 +36,23 @@ _python_ = TestSCons._python_
 
 test = TestSCons.TestSCons()
 
-# Keep this logic because it skips the test if javac or jar not found.
 where_javac, java_version = test.java_where_javac()
 where_jar = test.java_where_jar()
 
-test.write('myjar.py', r"""
-import sys
-args = sys.argv[1:]
-while args:
-    a = args[0]
-    if a == 'cf':
-        out = args[1]
-        args = args[1:]
-    else:
-        break
-    args = args[1:]
-outfile = open(out, 'w')
-for file in args:
-    infile = open(file, 'r')
-    for l in infile.readlines():
-        if l[:7] != '/*jar*/':
-            outfile.write(l)
-sys.exit(0)
-""")
-
-test.write('SConstruct', """
-DefaultEnvironment(tools=[])
-env = Environment(tools = ['jar'],
-                  JAR = r'%(_python_)s myjar.py')
-env.Jar(target = 'test1.jar', source = 'test1.class')
-""" % locals())
-
-test.write('test1.class', """\
-test1.class
-/*jar*/
-line 3
-""")
-
-test.run(arguments='.', stderr=None)
-
-test.must_match('test1.jar', "test1.class\nline 3\n", mode='r')
-
-if os.path.normcase('.class') == os.path.normcase('.CLASS'):
-
-    test.write('SConstruct', """
-DefaultEnvironment(tools=[])
-env = Environment(tools = ['jar'],
-                  JAR = r'%(_python_)s myjar.py')
-env.Jar(target = 'test2.jar', source = 'test2.CLASS')
-""" % locals())
-
-    test.write('test2.CLASS', """\
-test2.CLASS
-/*jar*/
-line 3
-""")
-
-    test.run(arguments='.', stderr=None)
-
-    test.must_match('test2.jar', "test2.CLASS\nline 3\n", mode='r')
-
-test.write('myjar2.py', r"""
-import sys
-f=open(sys.argv[2], 'w')
-f.write(" ".join(sys.argv[1:]))
-f.write("\n")
-f.close()
-sys.exit(0)
-""")
-
-test.write('SConstruct', """
-DefaultEnvironment(tools=[])
-env = Environment(tools = ['jar'],
-                  JAR = r'%(_python_)s myjar2.py',
-                  JARFLAGS='cvf')
-env.Jar(target = 'classes.jar', source = [ 'testdir/bar.class',
-                                           'foo.mf' ],
-        TESTDIR='testdir',
-        JARCHDIR='$TESTDIR')
-""" % locals())
-
-test.subdir('testdir')
-test.write(['testdir', 'bar.class'], 'foo')
-test.write('foo.mf',
-           """Manifest-Version : 1.0
-           blah
-           blah
-           blah
-           """)
-test.run(arguments='classes.jar')
-test.must_match('classes.jar',
-                'cvfm classes.jar foo.mf -C testdir bar.class\n', mode='r')
-
 test.file_fixture('wrapper_with_args.py')
 
-test.write('SConstruct', """
+test.write('SConstruct', """\
 DefaultEnvironment(tools=[])
-foo = Environment(tools = ['javac', 'jar'])
+foo = Environment(tools=['javac', 'jar'])
 # jar = foo.Dictionary('JAR')
-bar = foo.Clone(JAR = r'%(_python_)s wrapper_with_args.py jar')
-foo.Java(target = 'classes', source = 'com/sub/foo')
-bar.Java(target = 'classes', source = 'com/sub/bar')
-foo.Jar(target = 'foo', source = 'classes/com/sub/foo')
-bar.Jar(target = 'bar', source = Dir('classes/com/sub/bar'))
+bar = foo.Clone(JAR=r'%(_python_)s wrapper_with_args.py jar')
+foo.Java(target='classes', source='com/sub/foo')
+bar.Java(target='classes', source='com/sub/bar')
+foo.Jar(target='foo', source='classes/com/sub/foo')
+bar.Jar(target='bar', source=Dir('classes/com/sub/bar'))
 """ % locals())
 
-test.subdir('com',
-            ['com', 'sub'],
-            ['com', 'sub', 'foo'],
-            ['com', 'sub', 'bar'])
+test.subdir('com', ['com', 'sub'], ['com', 'sub', 'foo'], ['com', 'sub', 'bar'])
 
 test.write(['com', 'sub', 'foo', 'Example1.java'], """\
 package com.sub.foo;
@@ -228,13 +142,12 @@ test.run(arguments = '.')
 
 expected_wrapper_out = "wrapper_with_args.py jar cf bar.jar classes/com/sub/bar\n"
 expected_wrapper_out = expected_wrapper_out.replace('/', os.sep)
-test.must_match('wrapper.out',
-                expected_wrapper_out % locals(), mode='r')
+test.must_match('wrapper.out', expected_wrapper_out % locals(), mode='r')
 
 test.must_exist('foo.jar')
 test.must_exist('bar.jar')
 
-test.up_to_date(arguments = '.')
+test.up_to_date(arguments='.')
 
 #######
 # test java source files as source to Jar builder
@@ -250,22 +163,43 @@ test.write(['testdir2', 'SConstruct'], """
 DefaultEnvironment(tools=[])
 
 foo = Environment()
-foo.Jar(target = 'foobar', source = [
-    'com/javasource/JavaFile1.java', 
-    'com/javasource/JavaFile2.java',
-    'com/javasource/JavaFile3.java'
-])
-foo.Jar(target = ['foo', 'bar'], source = [
-    'com/javasource/JavaFile1.java', 
-    'com/javasource/JavaFile2.java',
-    'com/javasource/JavaFile3.java'
-])
-foo.Command("foobarTest", [], Mkdir("foobarTest") )
-foo.Command('foobarTest/com/javasource/JavaFile3.java', 'foobar.jar', foo['JAR'] + ' xvf ../foobar.jar', chdir='foobarTest')
-foo.Command("fooTest", [], Mkdir("fooTest") )
-foo.Command('fooTest/com/javasource/JavaFile3.java', 'foo.jar', foo['JAR'] + ' xvf ../foo.jar', chdir='fooTest')
-foo.Command("barTest", [], Mkdir("barTest") )
-foo.Command('barTest/com/javasource/JavaFile3.java', 'bar.jar', foo['JAR'] + ' xvf ../bar.jar', chdir='barTest')
+foo.Jar(
+    target='foobar',
+    source=[
+        'com/javasource/JavaFile1.java',
+        'com/javasource/JavaFile2.java',
+        'com/javasource/JavaFile3.java',
+    ],
+)
+foo.Jar(
+    target=['foo', 'bar'],
+    source=[
+        'com/javasource/JavaFile1.java',
+        'com/javasource/JavaFile2.java',
+        'com/javasource/JavaFile3.java',
+    ],
+)
+foo.Command("foobarTest", [], Mkdir("foobarTest"))
+foo.Command(
+    'foobarTest/com/javasource/JavaFile3.java',
+    'foobar.jar',
+    foo['JAR'] + ' xvf ../foobar.jar',
+    chdir='foobarTest',
+)
+foo.Command("fooTest", [], Mkdir("fooTest"))
+foo.Command(
+    'fooTest/com/javasource/JavaFile3.java',
+    'foo.jar',
+    foo['JAR'] + ' xvf ../foo.jar',
+    chdir='fooTest',
+)
+foo.Command("barTest", [], Mkdir("barTest"))
+foo.Command(
+    'barTest/com/javasource/JavaFile3.java',
+    'bar.jar',
+    foo['JAR'] + ' xvf ../bar.jar',
+    chdir='barTest',
+)
 """)
 
 test.write(['testdir2', 'com', 'javasource', 'JavaFile1.java'], """\
@@ -309,11 +243,7 @@ public class JavaFile3
 # use regex . for dirsep so this will work on both windows and other platforms.
 expect = ".*jar cf foo.jar -C com.javasource.JavaFile1 com.javasource.JavaFile1.class -C com.javasource.JavaFile2 com.javasource.JavaFile2.class -C com.javasource.JavaFile3 com.javasource.JavaFile3.class.*"
 
-test.run(chdir='testdir2',	
-         match=TestSCons.match_re_dotall,	
-         stdout = expect)
-
-
+test.run(chdir='testdir2', match=TestSCons.match_re_dotall, stdout=expect)
 
 #test single target jar
 test.must_exist(['testdir2','foobar.jar'])
@@ -338,12 +268,14 @@ test.must_exist(['testdir2', 'barTest', 'com', 'javasource', 'JavaFile3.class'])
 # test list of lists
 
 # make some directories to test in
-test.subdir('listOfLists',
-            ['manifest_dir'],
-            ['listOfLists', 'src'],
-            ['listOfLists', 'src', 'com'],
-            ['listOfLists', 'src', 'com', 'javasource'],
-            ['listOfLists', 'src', 'com', 'resource'])
+test.subdir(
+    'listOfLists',
+    ['manifest_dir'],
+    ['listOfLists', 'src'],
+    ['listOfLists', 'src', 'com'],
+    ['listOfLists', 'src', 'com', 'javasource'],
+    ['listOfLists', 'src', 'com', 'resource'],
+)
 
 # test varient dir and lists of lists
 test.write(['listOfLists', 'SConstruct'], """
@@ -352,15 +284,26 @@ DefaultEnvironment(tools=[])
 foo = Environment()
 foo.VariantDir('build', 'src', duplicate=0)
 foo.VariantDir('test', '../manifest_dir', duplicate=0)
-sourceFiles = ["src/com/javasource/JavaFile1.java", "src/com/javasource/JavaFile2.java", "src/com/javasource/JavaFile3.java",]
+sourceFiles = [
+    "src/com/javasource/JavaFile1.java",
+    "src/com/javasource/JavaFile2.java",
+    "src/com/javasource/JavaFile3.java",
+]
 list_of_class_files = foo.Java('build', source=sourceFiles)
 resources = ['build/com/resource/resource1.txt', 'build/com/resource/resource2.txt']
 for resource in resources:
-    foo.Command(resource, list_of_class_files, Copy(resource, resource.replace('build','src')))
+    foo.Command(
+        resource, list_of_class_files, Copy(resource, resource.replace('build', 'src'))
+    )
 contents = [list_of_class_files, resources]
-foo.Jar(target = 'lists', source = contents + ['test/MANIFEST.mf'], JARCHDIR='build')
-foo.Command("listsTest", [], Mkdir("listsTest") )
-foo.Command('listsTest/src/com/javasource/JavaFile3.java', 'lists.jar', foo['JAR'] + ' xvf ../lists.jar', chdir='listsTest')
+foo.Jar(target='lists', source=contents + ['test/MANIFEST.mf'], JARCHDIR='build')
+foo.Command("listsTest", [], Mkdir("listsTest"))
+foo.Command(
+    'listsTest/src/com/javasource/JavaFile3.java',
+    'lists.jar',
+    foo['JAR'] + ' xvf ../lists.jar',
+    chdir='listsTest',
+)
 """)
 
 test.write(['listOfLists', 'src', 'com', 'javasource', 'JavaFile1.java'], """\
@@ -431,25 +374,34 @@ test.must_contain(['listOfLists', 'listsTest', 'META-INF', 'MANIFEST.MF'], b"MyM
 # test different style of passing in dirs
 
 # make some directories to test in
-test.subdir('testdir3',
-            ['testdir3', 'com'],
-            ['testdir3', 'com', 'sub'],
-            ['testdir3', 'com', 'sub', 'foo'],
-            ['testdir3', 'com', 'sub', 'bar'])
+test.subdir(
+    'testdir3',
+    ['testdir3', 'com'],
+    ['testdir3', 'com', 'sub'],
+    ['testdir3', 'com', 'sub', 'foo'],
+    ['testdir3', 'com', 'sub', 'bar'],
+)
 
 # Create the jars then extract them back to check contents
 test.write(['testdir3', 'SConstruct'], """
 DefaultEnvironment(tools=[])
 
 foo = Environment()
-bar = foo.Clone()
-foo.Java(target = 'classes', source = 'com/sub/foo')
-bar.Java(target = 'classes', source = 'com/sub/bar')
-foo.Jar(target = 'foo', source = 'classes/com/sub/foo', JARCHDIR='classes')
-bar.Jar(target = 'bar', source = Dir('classes/com/sub/bar'), JARCHDIR='classes')
-foo.Command("fooTest", 'foo.jar', Mkdir("fooTest") )
+foo_cls = foo.Java(target='classes', source='com/sub/foo')
+foo_res = 'classes/com/sub/foo/NonJava.txt'
+foo_res_src = 'com/sub/foo/NonJava.txt'
+foo.Command(foo_res, foo_cls, Copy(foo_res, foo_res_src))
+foo.Jar(target='foo', source='classes/com/sub/foo', JARCHDIR='classes')
+foo.Command("fooTest", 'foo.jar', Mkdir("fooTest"))
 foo.Command('doesnt_exist1', "fooTest", foo['JAR'] + ' xvf ../foo.jar', chdir='fooTest')
-bar.Command("barTest", 'bar.jar', Mkdir("barTest") )
+
+bar = foo.Clone()
+bar_cls = bar.Java(target='classes', source='com/sub/bar')
+bar_res = 'classes/com/sub/bar/NonJava.txt'
+bar_res_src = 'com/sub/bar/NonJava.txt'
+bar.Command(bar_res, bar_cls, Copy(bar_res, bar_res_src))
+bar.Jar(target='bar', source=Dir('classes/com/sub/bar'), JARCHDIR='classes')
+bar.Command("barTest", 'bar.jar', Mkdir("barTest"))
 bar.Command('doesnt_exist2', 'barTest', bar['JAR'] + ' xvf ../bar.jar', chdir='barTest')
 """)
 
@@ -549,7 +501,6 @@ test.run(chdir='testdir3')
 
 # check the output and make sure the java files got converted to classes
 
-
 # make sure there are class in the jar
 test.must_exist(['testdir3','foo.jar'])
 test.must_exist(['testdir3', 'fooTest', 'com', 'sub', 'foo', 'Example1.class'])
@@ -557,7 +508,7 @@ test.must_exist(['testdir3', 'fooTest', 'com', 'sub', 'foo', 'Example2.class'])
 test.must_exist(['testdir3', 'fooTest', 'com', 'sub', 'foo', 'Example3.class'])
 # TODO: determine expected behavior with resource files, should they be 
 #       automatically copied in or specified in seperate commands
-#test.must_exist(['testdir3', 'fooTest', 'com', 'sub', 'foo', 'NonJava.txt'])
+test.must_exist(['testdir3', 'fooTest', 'com', 'sub', 'foo', 'NonJava.txt'])
 
 # make sure both jars got createds
 test.must_exist(['testdir3','bar.jar'])
@@ -566,11 +517,10 @@ test.must_exist(['testdir3', 'barTest', 'com', 'sub', 'bar', 'Example5.class'])
 test.must_exist(['testdir3', 'barTest', 'com', 'sub', 'bar', 'Example6.class'])
 # TODO: determine expected behavior with resource files, should they be 
 #       automatically copied in or specified in seperate commands
-#test.must_exist(['testdir3', 'fooTest', 'com', 'sub', 'bar', 'NonJava.txt'])
+test.must_exist(['testdir3', 'barTest', 'com', 'sub', 'bar', 'NonJava.txt'])
 
 test.pass_test()
 
-
 # Local Variables:
 # tab-width:4
 # indent-tabs-mode:nil
diff --git a/test/Java/JAVAC.py b/test/Java/JAVAC.py
index 20f7f96..f303e87 100644
--- a/test/Java/JAVAC.py
+++ b/test/Java/JAVAC.py
@@ -25,6 +25,8 @@
 
 """
 Test setting the JAVAC variable.
+
+This test does not require a JDK to operate.
 """
 
 import os
@@ -35,33 +37,11 @@ _python_ = TestSCons._python_
 
 test = TestSCons.TestSCons()
 
+test.file_fixture(['Java-fixture', 'myjavac.py'])
 
-
-test.write('myjavac.py', r"""
-import sys
-args = sys.argv[1:]
-while args:
-    a = args[0]
-    if a == '-d':
-        args = args[1:]
-    elif a == '-sourcepath':
-        args = args[1:]
-    else:
-        break
-    args = args[1:]
-for file in args:
-    infile = open(file, 'r')
-    outfile = open(file[:-5] + '.class', 'w')
-    for l in infile.readlines():
-        if l[:9] != '/*javac*/':
-            outfile.write(l)
-sys.exit(0)
-""")
-
-test.write('SConstruct', """
-env = Environment(tools = ['javac'],
-                  JAVAC = r'%(_python_)s myjavac.py')
-env.Java(target = '.', source = '.')
+test.write('SConstruct', """\
+env = Environment(tools=['javac'], JAVAC=r'%(_python_)s myjavac.py')
+env.Java(target='.', source='.')
 """ % locals())
 
 test.write('test1.java', """\
@@ -71,15 +51,12 @@ line 3
 """)
 
 test.run(arguments='.', stderr=None)
-
 test.must_match('test1.class', "test1.java\nline 3\n", mode='r')
 
 if os.path.normcase('.java') == os.path.normcase('.JAVA'):
-
     test.write('SConstruct', """\
-env = Environment(tools = ['javac'],
-                  JAVAC = r'%(_python_)s myjavac.py')
-env.Java(target = '.', source = '.')
+env = Environment(tools=['javac'], JAVAC=r'%(_python_)s myjavac.py')
+env.Java(target='.', source='.')
 """ % locals())
 
     test.write('test2.JAVA', """\
@@ -89,11 +66,8 @@ line 3
 """)
 
     test.run(arguments='.', stderr=None)
-
     test.must_match('test2.class', "test2.JAVA\nline 3\n", mode='r')
 
-
-
 test.pass_test()
 
 # Local Variables:
diff --git a/test/Java/Java-fixture/.exclude_tests b/test/Java/Java-fixture/.exclude_tests
new file mode 100644
index 0000000..37004e6
--- /dev/null
+++ b/test/Java/Java-fixture/.exclude_tests
@@ -0,0 +1,2 @@
+myjar.py
+myjavac.py
diff --git a/test/Java/Java-fixture/myjar.py b/test/Java/Java-fixture/myjar.py
new file mode 100644
index 0000000..a47e3b0
--- /dev/null
+++ b/test/Java/Java-fixture/myjar.py
@@ -0,0 +1,19 @@
+import fileinput
+import sys
+
+args = sys.argv[1:]
+while args:
+    arg = args[0]
+    if arg == 'cf':
+        out = args[1]
+        args = args[1:]
+    else:
+        break
+    args = args[1:]
+
+with open(out, 'wb') as ofp, fileinput.input(files=args, mode='rb') as ifp:
+    for line in ifp:
+        if not line.startswith(b'/*jar*/'):
+            ofp.write(line)
+
+sys.exit(0)
diff --git a/test/Java/Java-fixture/myjavac.py b/test/Java/Java-fixture/myjavac.py
new file mode 100644
index 0000000..1c7fdea
--- /dev/null
+++ b/test/Java/Java-fixture/myjavac.py
@@ -0,0 +1,21 @@
+import sys
+
+args = sys.argv[1:]
+while args:
+    arg = args[0]
+    if arg == '-d':
+        args = args[1:]
+    elif arg == '-sourcepath':
+        args = args[1:]
+    else:
+        break
+    args = args[1:]
+
+for file in args:
+    out = file.lower().replace('.java', '.class')
+    with open(file, 'rb') as infile, open(out, 'wb') as outfile:
+        for line in infile:
+            if not line.startswith(b'/*javac*/'):
+                outfile.write(line)
+
+sys.exit(0)
diff --git a/test/Java/jar_not_in_PATH.py b/test/Java/jar_not_in_PATH.py
index 26e92ce..b890ba1 100644
--- a/test/Java/jar_not_in_PATH.py
+++ b/test/Java/jar_not_in_PATH.py
@@ -35,33 +35,17 @@ _python_ = TestSCons._python_
 
 test = TestSCons.TestSCons()
 
-test.write('myjar.py', r"""
-import sys
-args = sys.argv[1:]
-while args:
-    a = args[0]
-    if a == 'cf':
-        out = args[1]
-        args = args[1:]
-    else:
-        break
-    args = args[1:]
-outfile = open(out, 'wb')
-for file in args:
-    infile = open(file, 'rb')
-    for l in infile.readlines():
-        if l[:7] != '/*jar*/':
-            outfile.write(l)
-sys.exit(0)
-""")
+test.file_fixture(['Java-fixture', 'myjar.py'])
 
-test.write('SConstruct', """
+test.write('SConstruct', """\
 import os
-oldpath = os.environ.get('PATH','')
-env = Environment(ENV = {'PATH' : ['.']})
+
+oldpath = os.environ.get('PATH', '')
+DefaultEnvironment(tools=[])
+env = Environment(ENV={'PATH': ['.']}, tools=['javac', 'jar'])
 env['ENV']['PATH'] = oldpath
 env['JAR'] = r'%(_python_)s ./myjar.py'
-env.Jar(target = 'test1.jar', source = 'test1.class')
+env.Jar(target='test1.jar', source='test1.class')
 """ % locals())
 
 test.write('test1.class', """\
@@ -70,7 +54,7 @@ test1.class
 line 3
 """)
 
-test.run(arguments = '.', stderr = None)
+test.run(arguments='.', stderr=None)
 
 test.must_exist('test1.jar')
 
diff --git a/test/Java/rmic_not_in_PATH.py b/test/Java/rmic_not_in_PATH.py
index ac3f28e..68a2c30 100644
--- a/test/Java/rmic_not_in_PATH.py
+++ b/test/Java/rmic_not_in_PATH.py
@@ -63,11 +63,13 @@ sys.exit(0)
 
 test.write('SConstruct', """
 import os
-oldpath = os.environ.get('PATH','')
-env = Environment(ENV = {'PATH' : ['.']})
+
+oldpath = os.environ.get('PATH', '')
+DefaultEnvironment(tools=[])
+env = Environment(ENV={'PATH': ['.']}, tools=['javac', 'rmic'])
 env['ENV']['PATH'] = oldpath
 env['RMIC'] = r'%(_python_)s myrmic.py'
-env.RMIC(target = 'outdir', source = 'test1.java')
+env.RMIC(target='outdir', source='test1.java')
 """ % locals())
 
 test.write('test1.java', """\
diff --git a/test/LEX/LEX.py b/test/LEX/LEX.py
index 79d8359..7dc8436 100644
--- a/test/LEX/LEX.py
+++ b/test/LEX/LEX.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,10 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
-
 
 import TestSCons
 
@@ -32,46 +30,29 @@ _exe   = TestSCons._exe
 
 test = TestSCons.TestSCons()
 
-
-
-test.write('mylex.py', """
-import getopt
-import sys
-if sys.platform == 'win32':
-    longopts = ['nounistd']
-else:
-    longopts = []
-cmd_opts, args = getopt.getopt(sys.argv[1:], 't', longopts)
-for a in args:
-    with open(a, 'rb') as f:
-        contents = f.read()
-    sys.stdout.write(contents.replace(b'LEX', b'mylex.py').decode())
-sys.exit(0)
-""")
+test.file_fixture('mylex.py')
 
 test.write('SConstruct', """
-env = Environment(LEX = r'%(_python_)s mylex.py', tools=['default', 'lex'])
-env.CFile(target = 'aaa', source = 'aaa.l')
-env.CFile(target = 'bbb', source = 'bbb.lex')
-env.CXXFile(target = 'ccc', source = 'ccc.ll')
-env.CXXFile(target = 'ddd', source = 'ddd.lm')
+env = Environment(LEX=r'%(_python_)s mylex.py', tools=['default', 'lex'])
+env.CFile(target='aaa', source='aaa.l')
+env.CFile(target='bbb', source='bbb.lex')
+env.CXXFile(target='ccc', source='ccc.ll')
+env.CXXFile(target='ddd', source='ddd.lm')
 """ % locals())
 
-test.write('aaa.l',         "aaa.l\nLEX\n")
-test.write('bbb.lex',       "bbb.lex\nLEX\n")
-test.write('ccc.ll',        "ccc.ll\nLEX\n")
-test.write('ddd.lm',        "ddd.lm\nLEX\n")
+test.write('aaa.l', "aaa.l\nLEX\n")
+test.write('bbb.lex', "bbb.lex\nLEX\n")
+test.write('ccc.ll', "ccc.ll\nLEX\n")
+test.write('ddd.lm', "ddd.lm\nLEX\n")
 
-test.run(arguments = '.', stderr = None)
+test.run(arguments='.', stderr=None)
 
 # Read in with mode='r' because mylex.py implicitley wrote to stdout
 # with mode='w'.
-test.must_match('aaa.c',    "aaa.l\nmylex.py\n",        mode='r')
-test.must_match('bbb.c',    "bbb.lex\nmylex.py\n",      mode='r')
-test.must_match('ccc.cc',   "ccc.ll\nmylex.py\n",       mode='r')
-test.must_match('ddd.m',    "ddd.lm\nmylex.py\n",       mode='r')
-
-
+test.must_match('aaa.c', "aaa.l\nmylex.py\n", mode='r')
+test.must_match('bbb.c', "bbb.lex\nmylex.py\n", mode='r')
+test.must_match('ccc.cc', "ccc.ll\nmylex.py\n", mode='r')
+test.must_match('ddd.m', "ddd.lm\nmylex.py\n", mode='r')
 
 test.pass_test()
 
diff --git a/test/LEX/LEXFLAGS.py b/test/LEX/LEXFLAGS.py
index efcf9c4..f7d16c1 100644
--- a/test/LEX/LEXFLAGS.py
+++ b/test/LEX/LEXFLAGS.py
@@ -35,28 +35,7 @@ test = TestSCons.TestSCons()
 
 test.subdir('in')
 
-test.write('mylex.py', """
-import getopt
-import sys
-import os
-if sys.platform == 'win32':
-    longopts = ['nounistd']
-else:
-    longopts = []
-cmd_opts, args = getopt.getopt(sys.argv[1:], 'I:tx', longopts)
-opt_string = ''
-i_arguments = ''
-for opt, arg in cmd_opts:
-    if opt == '-I': i_arguments = i_arguments + ' ' + arg
-    else: opt_string = opt_string + ' ' + opt
-for a in args:
-    with open(a, 'r') as f:
-        contents = f.read()
-    contents = contents.replace('LEXFLAGS', opt_string)
-    contents = contents.replace('I_ARGS', i_arguments)
-    sys.stdout.write(contents)
-sys.exit(0)
-""")
+test.file_fixture('mylex.py')
 
 test.write('SConstruct', """
 env = Environment(
@@ -76,9 +55,7 @@ if sys.platform == 'win32' and not sysconfig.get_platform() in ("mingw",):
     lexflags = ' --nounistd' + lexflags
 # Read in with mode='r' because mylex.py implicitley wrote to stdout
 # with mode='w'.
-test.must_match(['out', 'aaa.c'],	"aaa.l\n%s\n out in\n" % lexflags, mode='r')
-
-
+test.must_match(['out', 'aaa.c'], "aaa.l\n%s\n out in\n" % lexflags, mode='r')
 
 test.pass_test()
 
diff --git a/test/fixture/mycompile.py b/test/fixture/mycompile.py
index 0f37d19..15a1c6f 100644
--- a/test/fixture/mycompile.py
+++ b/test/fixture/mycompile.py
@@ -1,19 +1,30 @@
-r"""
-Phony "compiler" for testing SCons.
+"""
+Phony compiler for testing SCons.
+
+Copies its source files to the target file, dropping lines that match
+a pattern, so we can recognize the tool has made a modification.
+Intended for use as a *COM construction variable.
+
+Calling convention is:
+  argv[1] the function of the script (cc, c++, as, link etc.)
+  argv[2] the output file to write
+  argv[3:] one or more input files to "compile"
 
-Copies its source files to the target file, dropping lines
-that match a pattern, so we can recognize the tool
-has made a modification.
+Invocation often looks like:
+  Environment(CCCOM = r'%(_python_)s mycompile.py cc $TARGET $SOURCE', ...
 """
 
+import fileinput
 import sys
 
+def fake_compile():
+    skipline = f"/*{sys.argv[1]}*/\n".encode("utf-8")
+    with open(sys.argv[2], 'wb') as ofp, fileinput.input(files=sys.argv[3:], mode='rb') as ifp:
+        for line in ifp:
+            if line != skipline:
+                ofp.write(line)
+
+
 if __name__ == '__main__':
-    line = ('/*' + sys.argv[1] + '*/\n').encode()
-    with open(sys.argv[2], 'wb') as ofp:
-        for f in sys.argv[3:]:
-            with open(f, 'rb') as ifp:
-                lines = [ln for ln in ifp if ln != line]
-                for ln in lines:
-                    ofp.write(ln)
+    fake_compile()
     sys.exit(0)
diff --git a/test/fixture/mygcc.py b/test/fixture/mygcc.py
index ceb10e5..91ca386 100644
--- a/test/fixture/mygcc.py
+++ b/test/fixture/mygcc.py
@@ -1,18 +1,35 @@
+"""
+Phony compiler for testing SCons.
+
+Copies its source file to the target file, dropping lines that match
+a pattern, so we can recognize the tool has made a modification.
+
+The first argument is the language (cc, c__, g77, etc.).
+
+Recognizes a -x option to append the language to 'mygcc.out'
+for tracing purposes.
+
+Intended for use as $CC, $CXX, etc.
+"""
+
 import getopt
 import sys
 
-compiler = sys.argv[1]
-clen = len(compiler) + 1
-opts, args = getopt.getopt(sys.argv[2:], 'co:xf:K:')
-for opt, arg in opts:
-    if opt == '-o':
-        out = arg
-    elif opt == '-x':
-        with open('mygcc.out', 'a') as f:
-            f.write(compiler + "\n")
-
-with open(out, 'w') as ofp, open(args[0], 'r') as ifp:
-    for line in ifp.readlines():
-        if line[:clen] != '#' + compiler:
-            ofp.write(line)
-sys.exit(0)
+def fake_gcc():
+    compiler = sys.argv[1].encode('utf-8')
+    opts, args = getopt.getopt(sys.argv[2:], 'co:xf:K:')
+    for opt, arg in opts:
+        if opt == '-o':
+            out = arg
+        elif opt == '-x':
+            with open('mygcc.out', 'ab') as logfile:
+                logfile.write(compiler + b"\n")
+
+    with open(out, 'wb') as ofp, open(args[0], 'rb') as ifp:
+        for line in ifp:
+            if not line.startswith(b'#' + compiler):
+                ofp.write(line)
+
+if __name__ == '__main__':
+    fake_gcc()
+    sys.exit(0)
diff --git a/test/fixture/mylex.py b/test/fixture/mylex.py
new file mode 100644
index 0000000..8f47049
--- /dev/null
+++ b/test/fixture/mylex.py
@@ -0,0 +1,36 @@
+"""
+Phony lex for testing SCons.
+
+Writes the contents of input file to stdout,
+after "substituting" $LEXFLAGS and $I_ARGS
+
+Intended for use as $LEX
+"""
+
+import getopt
+import sys
+
+def fake_lex():
+    if sys.platform == 'win32':
+        longopts = ['nounistd']
+    else:
+        longopts = []
+    cmd_opts, args = getopt.getopt(sys.argv[1:], 'I:tx', longopts)
+    opt_string = ''
+    i_arguments = ''
+    for opt, arg in cmd_opts:
+        if opt == '-I':
+            i_arguments = f'{i_arguments} {arg}'
+        else:
+            opt_string = f'{opt_string} {opt}'
+    for arg in args:
+        with open(arg, 'rb') as ifp:
+            contents = ifp.read().decode(encoding='utf-8')
+        contents = contents.replace('LEXFLAGS', opt_string)
+        contents = contents.replace('LEX', 'mylex.py')
+        contents = contents.replace('I_ARGS', i_arguments)
+        sys.stdout.write(contents)
+
+if __name__ == '__main__':
+    fake_lex()
+    sys.exit(0)
diff --git a/test/fixture/mylink.py b/test/fixture/mylink.py
index 19969f0..f462655 100644
--- a/test/fixture/mylink.py
+++ b/test/fixture/mylink.py
@@ -1,6 +1,11 @@
 """
-Dummy linker for use by tests"
+Phony linker for testing SCons.
+
+Copies its source files to the target file, dropping lines that match
+a pattern, so we can recognize the tool has made a modification.
+Intended for use as the $LINK construction variable.
 """
+import fileinput
 import getopt
 import sys
 
@@ -10,34 +15,32 @@ def fake_link():
         if opt == '-o':
             out = arg
 
-    with open(out, 'w') as ofp:
-        for f in args:
-            with open(f, 'r') as ifp:
-                for line in ifp.readlines():
-                    if line[:5] != '#link':
-                        ofp.write(line)
-    sys.exit(0)
+    with open(out, 'wb') as ofp, fileinput.input(files=args, mode='rb') as ifp:
+        for line in ifp:
+            if not line.startswith(b'#link'):
+                ofp.write(line)
 
 def fake_win32_link():
     args = sys.argv[1:]
     while args:
-        a = args[0]
-        if a == '-o':
+        arg = args[0]
+        if arg == '-o':
             out = args[1]
             args = args[2:]
             continue
-        if not a[0] in '/-':
+        if arg[0] not in '/-':
             break
         args = args[1:]
-        if a[:5].lower() == '/out:': out = a[5:]
+        if arg.lower().startswith('/out:'):
+            out = arg[5:]
     with open(args[0], 'rb') as ifp, open(out, 'wb') as ofp:
-        for line in ifp.readlines():
+        for line in ifp:
             if not line.startswith(b'#link'):
                 ofp.write(line)
-    sys.exit(0)
 
 if __name__ == '__main__':
     if sys.platform == 'win32':
         fake_win32_link()
     else:
         fake_link()
+    sys.exit(0)
diff --git a/test/fixture/mylink_win32.py b/test/fixture/mylink_win32.py
deleted file mode 100644
index 477fc95..0000000
--- a/test/fixture/mylink_win32.py
+++ /dev/null
@@ -1,16 +0,0 @@
-import sys
-
-args = sys.argv[1:]
-while args:
-    a = args[0]
-    if a[0] != '/':
-        break
-    args.pop(0)
-    if a[:5] == '/OUT:':
-        out = a[5:]
-
-with open(out, 'w') as ofp, open(args[0], 'r') as ifp:
-    for line in ifp.readlines():
-        if line[:5] != '#link':
-            ofp.write(line)
-sys.exit(0)
diff --git a/test/fixture/myrewrite.py b/test/fixture/myrewrite.py
index 6914611..eb83cac 100644
--- a/test/fixture/myrewrite.py
+++ b/test/fixture/myrewrite.py
@@ -2,16 +2,19 @@ r"""
 Phony tool to modify a file in place for testing SCons.
 
 Drops lines that match a pattern.  Currently used to test
-ranlib-related behavior without invoking ranlib.
+ranlib and ar behavior without actually invoking those tools.
 """
 
 import sys
 
-if __name__ == '__main__':
-    line = ('/*' + sys.argv[1] + '*/\n').encode()
+def rewrite():
+    line = ('/*' + sys.argv[1] + '*/\n').encode('utf-8')
     with open(sys.argv[2], 'rb') as ifp:
         lines = [ln for ln in ifp if ln != line]
     with open(sys.argv[2], 'wb') as ofp:
-        for ln in lines:
-            ofp.write(ln)
+        ofp.writelines(lines)
+
+
+if __name__ == '__main__':
+    rewrite()
     sys.exit(0)
diff --git a/test/fixture/wrapper.py b/test/fixture/wrapper.py
index 112186e..c266cfa 100644
--- a/test/fixture/wrapper.py
+++ b/test/fixture/wrapper.py
@@ -1,3 +1,10 @@
+"""
+Command wrapper, for testing SCons.
+
+Writes the command name to file "wrapper.out",
+then passes the command line on to subprocess.
+No checking is done.
+"""
 import os
 import sys
 import subprocess
@@ -7,4 +14,4 @@ if __name__ == '__main__':
     if '--version' not in sys.argv and '-dumpversion' not in sys.argv:
         with open(path, 'wb') as f:
             f.write(b"wrapper.py\n")
-    subprocess.run(sys.argv[1:])
+    subprocess.run(sys.argv[1:], check=False)
diff --git a/test/fixture/wrapper_with_args.py b/test/fixture/wrapper_with_args.py
index b8d6ae5..769aea4 100644
--- a/test/fixture/wrapper_with_args.py
+++ b/test/fixture/wrapper_with_args.py
@@ -1,3 +1,10 @@
+"""
+Command wrapper taking arguments, for testing SCons.
+
+Writes the command name and argument list to file "wrapper.out",
+then passes the command line on to subprocess.
+No checking is done.
+"""
 import os
 import sys
 import subprocess
@@ -6,4 +13,4 @@ if __name__ == '__main__':
     path = os.path.join(os.path.dirname(os.path.relpath(__file__)), 'wrapper.out')
     with open(path, 'a') as f:
         f.write("wrapper_with_args.py %s\n" % " ".join(sys.argv[1:]))
-    subprocess.run(sys.argv[1:])
+    subprocess.run(sys.argv[1:], check=False)