FindTIFF: Add imported targets and update documentation

- Add TIFF::TIFF imported target
- Document imported target
- Add testcase to test the standard variables and the imported
  target

Also:

- Add TIFF_INCLUDE_DIRS to match common practice
- Update documentation generally, including documenting
  TIFF_INCLUDE_DIRS

2 files changed, 29 insertions, 0 deletions

diff --git a/Tests/FindTIFF/Test/CMakeLists.txt b/Tests/FindTIFF/Test/CMakeLists.txt
new file mode 100644
index 0000000..f17cda7
--- /dev/null
+++ b/Tests/FindTIFF/Test/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.1)
+project(TestFindTIFF C)
+include(CTest)
+
+# CMake does not actually provide FindTIFF publicly.
+set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../../../Source/Modules)
+
+find_package(TIFF REQUIRED)
+
+add_executable(test_xercesc_tgt main.c)
+target_link_libraries(test_xercesc_tgt TIFF::TIFF)
+add_test(NAME test_xercesc_tgt COMMAND test_xercesc_tgt)
+
+add_executable(test_xercesc_var main.c)
+target_include_directories(test_xercesc_var PRIVATE ${TIFF_INCLUDE_DIRS})
+target_link_libraries(test_xercesc_var PRIVATE ${TIFF_LIBRARIES})
+add_test(NAME test_xercesc_var COMMAND test_xercesc_var)
diff --git a/Tests/FindTIFF/Test/main.c b/Tests/FindTIFF/Test/main.c
new file mode 100644
index 0000000..fc4f337
--- /dev/null
+++ b/Tests/FindTIFF/Test/main.c
@@ -0,0 +1,12 @@
+#include <assert.h>
+#include <tiffio.h>
+
+int main()
+{
+  /* Without any TIFF file to open, test that the call fails as
+     expected.  This tests that linking worked. */
+  TIFF *tiff = TIFFOpen("invalid.tiff", "r");
+  assert(!tiff);
+
+  return 0;
+}