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

googletest/test/googletest-output-test-golden-lin.txt

@@ -12,7 +12,7 @@ Expected equality of these values:
   3
 Stack trace: (omitted)
 
-[==========] Running 84 tests from 39 test suites.
+[==========] Running 85 tests from 40 test suites.
 [----------] Global test environment set-up.
 FooEnvironment::SetUp() called.
 BarEnvironment::SetUp() called.
@@ -979,6 +979,12 @@ Expected failure
 Stack trace: (omitted)
 
 [  FAILED  ] PrintingStrings/ParamTest.Failure/a, where GetParam() = "a"
+[----------] 1 test from GoogleTestVerification
+[ RUN      ] GoogleTestVerification.UninstantiatedParamaterizedTestSuite<DetectNotInstantiatedTest>
+Paramaterized test suite DetectNotInstantiatedTest 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.
+
+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.)
+[       OK ] GoogleTestVerification.UninstantiatedParamaterizedTestSuite<DetectNotInstantiatedTest>
 [----------] Global test environment tear-down
 BarEnvironment::TearDown() called.
 googletest-output-test_.cc:#: Failure
@@ -992,8 +998,8 @@ Failed
 Expected fatal failure.
 Stack trace: (omitted)
 
-[==========] 84 tests from 39 test suites ran.
-[  PASSED  ] 30 tests.
+[==========] 85 tests from 40 test suites ran.
+[  PASSED  ] 31 tests.
 [  FAILED  ] 54 tests, listed below:
 [  FAILED  ] NonfatalFailureTest.EscapesStringOperands
 [  FAILED  ] NonfatalFailureTest.DiffForLongStrings