Add integration tests for processing defines

Note for now we only analyze each file for itself. Defines specified in
header A which is then included in header B do not yet influence the
defines processing in header B.

test/aspect/defines/BUILD

@@ -4,3 +4,20 @@ cc_library(
     deps = ["//test/aspect/defines/lib:a"],
 )
 
+cc_library(
+    name = "defines_from_bazel_target",
+    hdrs = ["defines_from_bazel_target.h"],
+    copts = ["-DSOME_COPT 42"],
+    defines = ["SOME_DEFINE"],
+    local_defines = ["LOCAL_DEFINE"],
+    deps = ["//test/aspect/defines/lib:a"],
+)
+
+cc_library(
+    name = "transitive_defines_from_bazel_target",
+    hdrs = ["transitive_defines_from_bazel_target.h"],
+    deps = [
+        "//test/aspect/defines/lib:a",
+        "//test/aspect/defines/support:transitive_define",
+    ],
+)

test/aspect/defines/README.md

@@ -0,0 +1,11 @@
+Defines can influence which include statements are relevant.
+
+These tests concentrate on parsing single files based on defines:
+
+- specified in the parsed file itself
+- coming from the C/C++ toolchain
+- defined by the Bazel target attributes `defines`, `local_defines` or `cops`
+
+Defines can also be imported into a file via an included header which specifies a define.
+This use case is not yet supported.
+We might add it at a later stage.

test/aspect/defines/defines_from_bazel_target.h

@@ -0,0 +1,17 @@
+#ifdef SOME_DEFINE
+#include "test/aspect/defines/lib/a.h"
+#else
+#include "test/aspect/defines/lib/b.h"
+#endif
+
+#ifdef LOCAL_DEFINE
+#include "test/aspect/defines/lib/a.h"
+#else
+#include "test/aspect/defines/lib/b.h"
+#endif
+
+#if SOME_COPT > 40
+#include "test/aspect/defines/lib/a.h"
+#else
+#include "test/aspect/defines/lib/b.h"
+#endif

test/aspect/defines/support/BUILD

@@ -0,0 +1,7 @@
+cc_library(
+    name = "transitive_define",
+    copts = ["-DLOCAL_COPT"],  # should not influence other targets
+    defines = ["TRANSITIVE_DEFINE"],
+    local_defines = ["LOCAL_DEFINE"],  # should not influence other targets
+    visibility = ["//test/aspect/defines:__pkg__"],
+)

test/aspect/defines/transitive_defines_from_bazel_target.h

@@ -0,0 +1,18 @@
+// Define introduced through target on which we depend. The target uses the attribute 'defines' which is propagated to
+// all users of the target.
+#ifdef TRANSITIVE_DEFINE
+#include "test/aspect/defines/lib/a.h"
+#else
+#include "test/aspect/defines/lib/b.h"
+#endif
+
+// The following defines shall never be active as they are set though Bazel target attributes 'copts' and
+// 'local_defines' which should not leak to users of the target
+
+#ifdef LOCAL_DEFINE
+#include "test/aspect/defines/lib/b.h"
+#endif
+
+#ifdef LOCAL_COPT
+#include "test/aspect/defines/lib/b.h"
+#endif

test/aspect/execute_tests.py

@@ -296,6 +296,22 @@
         ),
         expected=ExpectedResult(success=True),
     ),
+    TestCase(
+        name="defines_from_bazel_target",
+        cmd=TestCmd(
+            target="//test/aspect/defines:defines_from_bazel_target",
+            aspect=DEFAULT_ASPECT,
+        ),
+        expected=ExpectedResult(success=True),
+    ),
+    TestCase(
+        name="transitive_defines_from_bazel_target",
+        cmd=TestCmd(
+            target="//test/aspect/defines:transitive_defines_from_bazel_target",
+            aspect=DEFAULT_ASPECT,
+        ),
+        expected=ExpectedResult(success=True),
+    ),
 ]
 
 if __name__ == "__main__":