Add a simple automated test

This loads and saves various supported formats, and asserts that the
same pixels (or close enough) end up in the output files.

For a distribution that knows it intends to support particular formats,
if an environment variable like SVG_IMAGE_TEST_REQUIRE_LOAD_JPG or
SVG_IMAGE_TEST_REQUIRE_SAVE_JPG is set, the test will fail if the given
format is not available.

Signed-off-by: Simon McVittie <smcv@debian.org>

Author: smcv

CMakeLists.txt

@@ -239,6 +239,8 @@ include(CMakeDependentOption)
 include(CMakePackageConfigHelpers)
 include(GNUInstallDirs)
 
+option(BUILD_TESTS "Build unit tests?" OFF)
+cmake_dependent_option(INSTALL_TESTS "Install unit tests?" OFF BUILD_TESTS OFF)
 option(VENDORED_DEFAULT "Default value for *_VENDORED options. Can be overridden for each library. Is only used in the first configure run." ON)
 option(SDL2_IMAGE_DISABLE_INSTALL "Disable installing SDL2_image" OFF)
 
@@ -767,3 +769,8 @@ if (BUILD_SAMPLES)
         endif()
     endforeach()
 endif()
+
+if (BUILD_TESTS)
+  include(CTest)
+  add_subdirectory(test)
+endif()

Makefile.am

@@ -74,6 +74,12 @@ noinst_PROGRAMS = showimage showanim
 showimage_LDADD = libSDL2_image.la
 showanim_LDADD = libSDL2_image.la
 
+SUBDIRS = .
+
+if BUILD_TESTS
+SUBDIRS += test
+endif
+
 # Rule to build tar-gzipped distribution package
 $(PACKAGE)-$(VERSION).tar.gz: distcheck
 

configure.ac

@@ -250,6 +250,12 @@ AC_ARG_ENABLE([webp-shared], [AS_HELP_STRING([--enable-webp-shared], [dynamicall
  [], [enable_webp_shared=yes])
 AC_ARG_ENABLE([qoi], [AS_HELP_STRING([--enable-qoi], [support loading QOI images [default=yes]])],
  [], [enable_qoi=yes])
+AC_ARG_ENABLE([tests],
+              [AS_HELP_STRING([--enable-tests], [build tests [default=no]])],
+              [], [enable_tests=no])
+AC_ARG_ENABLE([installed-tests],
+              [AS_HELP_STRING([--enable-installed-tests], [install tests [default=no]])],
+              [], [enable_installed_tests=no])
 
 dnl Check for SDL
 SDL_VERSION=2.0.8
@@ -665,6 +671,9 @@ AC_SUBST([IMG_LIBS])
 AC_SUBST([PC_LIBS])
 AC_SUBST([PC_REQUIRES])
 
+AM_CONDITIONAL([BUILD_TESTS], [test "x$enable_tests" = xyes])
+AM_CONDITIONAL([INSTALL_TESTS], [test "x$enable_installed_tests" = xyes])
+
 dnl check for GCC warning options
 CheckWarnAll
 
@@ -678,5 +687,6 @@ AC_CONFIG_FILES([
 Makefile
 SDL2_image.spec
 SDL2_image.pc
+test/Makefile
 ])
 AC_OUTPUT

test/.gitignore

@@ -0,0 +1,5 @@
+/*.test
+/CompareSurfaces*.bmp
+/save-*.bmp
+/save.*
+/testimage

test/CMakeLists.txt

@@ -0,0 +1,75 @@
+add_executable(testimage main.c)
+
+set(ALL_TESTS
+    testimage
+)
+set(RESOURCE_FILES
+    palette.bmp
+    palette.gif
+    sample.avif
+    sample.bmp
+    sample.cur
+    sample.ico
+    sample.jpg
+    sample.jxl
+    sample.png
+    sample.pnm
+    sample.qoi
+    sample.tif
+    sample.webp
+    sample.xcf
+    sample.xpm
+    svg.bmp
+    svg.svg
+    svg64.bmp
+)
+
+set(TESTS_ENVIRONMENT
+    "SDL_TEST_SRCDIR=${CMAKE_CURRENT_SOURCE_DIR}"
+    "SDL_TEST_BUILDDIR=${CMAKE_CURRENT_BINARY_DIR}"
+    "SDL_VIDEODRIVER=dummy"
+)
+
+foreach(prog ${ALL_TESTS})
+    target_compile_definitions(${prog} PRIVATE $<TARGET_PROPERTY:SDL2_image,COMPILE_DEFINITIONS>)
+    target_link_libraries(${prog} PRIVATE SDL2_image::${sdl2_image_export_name})
+    if (TARGET SDL2::SDL2main)
+        target_link_libraries(${prog} PRIVATE SDL2::SDL2main)
+    endif()
+    target_link_libraries(${prog} PRIVATE SDL2_test)
+    if (BUILD_SHARED_LIBS)
+        target_link_libraries(${prog} PRIVATE SDL2::SDL2)
+    else()
+        target_link_libraries(${prog} PRIVATE SDL2::SDL2-static)
+    endif()
+
+    add_test(
+        NAME ${prog}
+        COMMAND ${prog}
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+    )
+    set_tests_properties(
+        ${prog}
+        PROPERTIES ENVIRONMENT "${TESTS_ENVIRONMENT}"
+    )
+    if(INSTALL_TESTS)
+        set(exe ${prog})
+        set(installedtestsdir "${CMAKE_INSTALL_FULL_LIBEXECDIR}/installed-tests/${CMAKE_PROJECT_NAME}")
+        configure_file(template.test.in "${exe}.test" @ONLY)
+        install(
+            FILES "${CMAKE_CURRENT_BINARY_DIR}/${exe}.test"
+            DESTINATION "${CMAKE_INSTALL_DATADIR}/installed-tests/${CMAKE_PROJECT_NAME}"
+        )
+    endif()
+endforeach()
+
+if(INSTALL_TESTS)
+    install(
+        TARGETS ${ALL_TESTS}
+        DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}/installed-tests/${CMAKE_PROJECT_NAME}"
+    )
+    install(
+        FILES ${RESOURCE_FILES}
+        DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}/installed-tests/${CMAKE_PROJECT_NAME}"
+    )
+endif()

test/Makefile.am

@@ -0,0 +1,69 @@
+testmetadir = $(datadir)/installed-tests/$(PACKAGE_TARNAME)
+testexecdir = $(libexecdir)/installed-tests/$(PACKAGE_TARNAME)
+
+test_programs = \
+	testimage \
+	$(NULL)
+
+testimage_CPPFLAGS = -I$(top_srcdir)
+testimage_SOURCES = main.c
+testimage_LDADD = \
+	../libSDL2_image.la \
+	$(SDL_LIBS) \
+	-lSDL2_test \
+	$(NULL)
+
+AM_TESTS_ENVIRONMENT = \
+	SDL_TEST_SRCDIR=$(abs_srcdir) \
+	SDL_TEST_BUILDDIR=$(abs_builddir) \
+	SDL_VIDEODRIVER=dummy \
+	$(NULL)
+
+if INSTALL_TESTS
+testexec_PROGRAMS = $(test_programs)
+else
+noinst_PROGRAMS = $(test_programs)
+endif
+
+TESTS = $(test_programs)
+
+if INSTALL_TESTS
+dist_testexec_DATA = \
+	palette.bmp \
+	palette.gif \
+	sample.avif \
+	sample.bmp \
+	sample.cur \
+	sample.ico \
+	sample.jpg \
+	sample.jxl \
+	sample.png \
+	sample.pnm \
+	sample.qoi \
+	sample.tif \
+	sample.webp \
+	sample.xcf \
+	sample.xpm \
+	svg.bmp \
+	svg.svg \
+	svg64.bmp \
+	$(NULL)
+
+all-local: generatetestmeta
+generatetestmeta:
+	rm -f *.test
+	set -e; for exe in $(test_programs); do \
+		sed \
+			-e 's#@installedtestsdir@#$(testexecdir)#g' \
+			-e "s#@exe@#$$exe#g" \
+			< $(srcdir)/template.test.in > $$exe.test; \
+	done
+
+install-data-hook: installtestmeta
+installtestmeta: generatetestmeta
+	install -m644 -D -t $(DESTDIR)$(testmetadir) *.test
+
+clean-local:
+	rm -f *.test
+	rm -f save.jpg save.bmp CompareSurfaces*.bmp
+endif