Googletest export

Detect when C++ parametric tests (TEST_P) are not instantiated.

When an un-instantiated TEST_P is found, a new test will be inserted that will emit a warning message.

This can be made to error with minor code edits.
In the future, that is intended to be the default.

PiperOrigin-RevId: 284901666

1 files changed, 60 insertions, 0 deletions

diff --git a/googletest/src/gtest.cc b/googletest/src/gtest.cc
index 3dbf8041..f6466b92 100644
--- a/googletest/src/gtest.cc
+++ b/googletest/src/gtest.cc
@@ -407,6 +407,66 @@ void AssertHelper::operator=(const Message& message) const {
                       );  // NOLINT
 }
 
+namespace {
+
+// When TEST_P is found without a matching INSTANTIATE_TEST_SUITE_P
+// to creates test cases for it, a syntetic test case is
+// inserted to report ether an error or a log message.
+//
+// This configuration bit will likely be removed at some point.
+constexpr bool kErrorOnUninstantiatedParameterizedTest = false;
+
+// A test that fails at a given file/line location with a given message.
+class FailureTest : public Test {
+ public:
+  explicit FailureTest(const CodeLocation& loc, std::string error_message,
+                       bool as_error)
+      : loc_(loc),
+        error_message_(std::move(error_message)),
+        as_error_(as_error) {}
+
+  void TestBody() override {
+    if (as_error_) {
+      AssertHelper(TestPartResult::kNonFatalFailure, loc_.file.c_str(),
+                   loc_.line, "") = Message() << error_message_;
+    } else {
+      std::cout << error_message_ << std::endl;
+    }
+  }
+
+ private:
+  const CodeLocation loc_;
+  const std::string error_message_;
+  const bool as_error_;
+};
+
+
+}  // namespace
+
+// If this parameterized test suite has no instantiations (and that
+// has not been marked as okay), emit a test case reporting that.
+void InsertSyntheticTestCase(const std::string &name, CodeLocation location) {
+  std::string message =
+      "Paramaterized test suite " + name +
+      " is defined via TEST_P, but never instantiated. None of the test cases "
+      "will run. Either no INSTANTIATE_TEST_SUITE_P is provided or the only "
+      "ones provided expand to nothing."
+      "\n\n"
+      "Ideally, TEST_P definitions should only ever be included as part of "
+      "binaries that intend to use them. (As opposed to, for example, being "
+      "placed in a library that may be linked in to get other utilities.)";
+
+  std::string full_name = "UninstantiatedParamaterizedTestSuite<" + name + ">";
+  RegisterTest(  //
+      "GoogleTestVerification", full_name.c_str(),
+      nullptr,  // No type parameter.
+      nullptr,  // No value parameter.
+      location.file.c_str(), location.line, [message, location] {
+        return new FailureTest(location, message,
+                               kErrorOnUninstantiatedParameterizedTest);
+      });
+}
+
 // A copy of all command line arguments.  Set by InitGoogleTest().
 static ::std::vector<std::string> g_argvs;