tests: port offset tests to Python

Use the test executable to generate files in a temporary location
and use difflib to compare their content.

This removes the requirement on "diff" for the test.

2 files changed, 52 insertions, 5 deletions

diff --git a/tests/offsets/Makefile.am b/tests/offsets/Makefile.am
index 0df9c151..fa1c1001 100644
--- a/tests/offsets/Makefile.am
+++ b/tests/offsets/Makefile.am
@@ -41,7 +41,9 @@ gitestoffsets_LDADD = $(top_builddir)/libgirepository-1.0.la $(GIREPO_LIBS)
 gitestoffsets.c: gen-gitestoffsets offsets.h Offsets-1.0.typelib
 	$(AM_V_GEN) $(PYTHON) $(srcdir)/gen-gitestoffsets $(srcdir)/offsets.h > $@ || ( rm -f $@ && false )
 
-EXTRA_DIST += gen-gitestoffsets
+EXTRA_DIST += \
+	gen-gitestoffsets \
+	test_offsets.py
 BUILT_SOURCES += gitestoffsets.c
 CLEANFILES += gitestoffsets.c $(EXTRA_PROGRAMS)
 
@@ -50,7 +52,5 @@ CLEANFILES += gitestoffsets.c $(EXTRA_PROGRAMS)
 # The trailing "echo" in LOG_COMPILER is used to ignore automake passing
 # gitestoffsets as we already run this in the same command line.
 TESTS = gitestoffsets
-LOG_COMPILER = env GI_TYPELIB_PATH=:$(top_builddir) ./gitestoffsets$(EXEEXT) offsets.compiled offsets.introspected && \
-	diff -u offsets.compiled offsets.introspected && echo
-
-CLEANFILES += offsets.compiled offsets.introspected
+TESTS_ENVIRONMENT = env top_builddir=$(top_builddir) builddir=$(builddir)
+LOG_COMPILER = $(PYTHON) $(srcdir)/test_offsets.py && echo
diff --git a/tests/offsets/test_offsets.py b/tests/offsets/test_offsets.py
new file mode 100755
index 00000000..db10f1c4
--- /dev/null
+++ b/tests/offsets/test_offsets.py
@@ -0,0 +1,47 @@
+import io
+import os
+import tempfile
+import difflib
+import contextlib
+import subprocess
+import unittest
+
+
+@contextlib.contextmanager
+def temp_filename(*args, **kwargs):
+    fd, name = tempfile.mkstemp(*args, **kwargs)
+    try:
+        os.close(fd)
+        yield name
+    finally:
+        os.unlink(name)
+
+
+class TestOffsets(unittest.TestCase):
+
+    def test_main(self):
+        gitestoffsets = os.path.join(os.environ["builddir"], "gitestoffsets")
+
+        env = os.environ.copy()
+        env["GI_TYPELIB_PATH"] = os.pathsep.join(
+            [os.environ["builddir"], os.environ["top_builddir"]])
+
+        with temp_filename(suffix=".compiled") as compiled_name, \
+                temp_filename(suffix=".introspected") as introspected_name:
+
+            subprocess.check_call(
+                [gitestoffsets, compiled_name, introspected_name], env=env)
+
+            with io.open(compiled_name, encoding="utf-8") as compiled, \
+                    io.open(introspected_name, encoding="utf-8") as introspected:
+
+                result = difflib.unified_diff(
+                    compiled.readlines(), introspected.readlines(),
+                    fromfile=compiled_name, tofile=introspected_name)
+                result = "".join(result)
+                if result:
+                    raise AssertionError(result)
+
+
+if __name__ == '__main__':
+    unittest.main()