bpo-38234: Fix test_embed.test_init_setpath_config() on FreeBSD (GH-16406)

Explicitly preinitializes with a Python preconfiguration to avoid
Py_SetPath() implicit preinitialization with a compat
preconfiguration.

Fix also test_init_setpath() and test_init_setpythonhome() on macOS:
use self.test_exe as the executable (and base_executable), rather
than shutil.which('python3').

1 files changed, 11 insertions, 1 deletions

diff --git a/Programs/_testembed.c b/Programs/_testembed.c
index 14fca24..83c266b 100644
--- a/Programs/_testembed.c
+++ b/Programs/_testembed.c
@@ -1448,6 +1448,17 @@ static int test_init_setpath(void)
 
 static int test_init_setpath_config(void)
 {
+    PyStatus status;
+    PyPreConfig preconfig;
+    PyPreConfig_InitPythonConfig(&preconfig);
+
+    /* Explicitly preinitializes with Python preconfiguration to avoid
+      Py_SetPath() implicit preinitialization with compat preconfiguration. */
+    status = Py_PreInitialize(&preconfig);
+    if (PyStatus_Exception(status)) {
+        Py_ExitStatusException(status);
+    }
+
     char *env = getenv("TESTPATH");
     if (!env) {
         fprintf(stderr, "missing TESTPATH env var\n");
@@ -1462,7 +1473,6 @@ static int test_init_setpath_config(void)
     PyMem_RawFree(path);
     putenv("TESTPATH=");
 
-    PyStatus status;
     PyConfig config;
 
     status = PyConfig_InitPythonConfig(&config);