Introduce GIT_ASSERT macros

Provide macros to replace usages of `assert`.  A true `assert` is
punishing as a library.  Instead we should do our best to not crash.

GIT_ASSERT_ARG(x) will now assert that the given argument complies to
some format and sets an error message and returns `-1` if it does not.

GIT_ASSERT(x) is for internal usage, and available as an internal
consistency check.  It will set an error message and return `-1` in the
event of failure.

1 files changed, 39 insertions, 0 deletions

diff --git a/tests/core/assert.c b/tests/core/assert.c
new file mode 100644
index 000000000..8fd709367
--- /dev/null
+++ b/tests/core/assert.c
@@ -0,0 +1,39 @@
+#include "clar_libgit2.h"
+
+static const char *hello_world = "hello, world";
+
+static int dummy_fn(const char *myarg)
+{
+	GIT_ASSERT_ARG(myarg);
+	GIT_ASSERT_ARG(myarg != hello_world);
+	return 0;
+}
+
+static int bad_math(void)
+{
+	GIT_ASSERT(1 + 1 == 3);
+	return 42;
+}
+
+void test_core_assert__argument(void)
+{
+	cl_git_fail(dummy_fn(NULL));
+	cl_assert(git_error_last());
+	cl_assert_equal_i(GIT_ERROR_INVALID, git_error_last()->klass);
+	cl_assert_equal_s("invalid argument: 'myarg'", git_error_last()->message);
+
+	cl_git_fail(dummy_fn(hello_world));
+	cl_assert(git_error_last());
+	cl_assert_equal_i(GIT_ERROR_INVALID, git_error_last()->klass);
+	cl_assert_equal_s("invalid argument: 'myarg != hello_world'", git_error_last()->message);
+
+	cl_git_pass(dummy_fn("foo"));
+}
+
+void test_core_assert__internal(void)
+{
+	cl_git_fail(bad_math());
+	cl_assert(git_error_last());
+	cl_assert_equal_i(GIT_ERROR_INTERNAL, git_error_last()->klass);
+	cl_assert_equal_s("unrecoverable internal error: '1 + 1 == 3'", git_error_last()->message);
+}