Clang: Add test for include collector

To be secure that include is only called it the definition is true.

Change-Id: I04bae9860e64206a1c6886d7cf1682a87e9f9a07
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

tests/unit/unittest/data/includecollector_false.h

@@ -0,0 +1,2 @@
+#pragma once
+

tests/unit/unittest/data/includecollector_if.cpp

@@ -0,0 +1,7 @@
+#if 0
+#include "includecollector_false.h"
+#endif
+
+#if 1
+#include "includecollector_true.h"
+#endif

tests/unit/unittest/data/includecollector_true.h

@@ -0,0 +1,2 @@
+#pragma once
+

tests/unit/unittest/includecollector-test.cpp

@@ -87,6 +87,16 @@ TEST_F(IncludeCollector, IncludesAreSorted)
                 ElementsAre(0, 1, 2));
 }
 
+TEST_F(IncludeCollector, If)
+{
+    emptyCollector.addFile(TESTDATA_DIR, "includecollector_if.cpp", "", {"cc", "includecollector_if.cpp"});
+
+    emptyCollector.collectIncludes();
+
+    ASSERT_THAT(emptyCollector.takeIncludeIds(),
+                ElementsAre(id(TESTDATA_DIR "/includecollector_true.h")));
+}
+
 TEST_F(IncludeCollector, LocalPath)
 {
     emptyCollector.addFile(TESTDATA_DIR, "includecollector_main.cpp", "", {"cc", "includecollector_main.cpp"});