tests: cmake: snippets: test DTS_EXTRA_CPPFLAGS

Add tests for the `DTS_EXTRA_CPPFLAGS` append option in snippets.

Signed-off-by: Jordan Yates <[email protected]>

Author: Jordan Yates

tests/cmake/snippets/snippets/foo/foo.overlay

@@ -4,4 +4,8 @@
 
 	/* This node will be deleted by the `bar` snippet if applied. */
 	added-by-foo {};
+
+#ifdef CMAKE_DTS_CONFIGURE
+	cmake-dts-configure {};
+#endif /* CMAKE_DTS_CONFIGURE */
 };

tests/cmake/snippets/snippets/foo/snippet.yml

@@ -2,3 +2,4 @@ name: foo
 append:
   EXTRA_CONF_FILE: foo.conf
   EXTRA_DTC_OVERLAY_FILE: foo.overlay
+  DTS_EXTRA_CPPFLAGS: -DCMAKE_DTS_CONFIGURE

tests/cmake/snippets/src/main.c

@@ -128,3 +128,14 @@ ZTEST(snippet_tests, test_dtc_overlay)
 		zassert(false, "Invalid test type");
 	}
 }
+
+ZTEST(snippet_tests, test_cmake_include)
+{
+	if (IS_ENABLED(CONFIG_TEST_TYPE_FOO) ||
+	    IS_ENABLED(CONFIG_TEST_TYPE_FOO_BAR) ||
+	    IS_ENABLED(CONFIG_TEST_TYPE_BAR_FOO)) {
+		zassert_true(DT_NODE_EXISTS(DT_PATH(cmake_dts_configure)));
+	} else {
+		zassert_false(DT_NODE_EXISTS(DT_PATH(cmake_dts_configure)));
+	}
+}