Fix tests' dependencies on gtest implementation details.

These tests rely on the exact failure messages generated by `ElementsAre()`, which are not part of gtest's public API and are subject to change without notice. If a test needs to verify matcher messages, it must only use matchers owned by the same project. It's never OK to depend on implementation details of code that one doesn't own.

PiperOrigin-RevId: 738045085
Change-Id: I5f84775808f751fa41aa76609394424649e027f1

Author: Tensorstore Team

tensorstore/array_testutil_test.cc

@@ -28,6 +28,7 @@ using ::tensorstore::MakeOffsetArray;
 using ::tensorstore::MakeScalarArray;
 using ::tensorstore::MatchesArray;
 using ::tensorstore::MatchesScalarArray;
+using ::testing::MatchesRegex;
 
 TEST(MatchesArrayTest, Describe) {
   std::ostringstream ss;
@@ -77,19 +78,18 @@ TEST(MatchesArrayTest, ExplainElementMatch) {
           {::testing::Not(::testing::ElementsAre('d')),
            ::testing::Not(::testing::ElementsAre('a', 'b'))}),
       MakeArray<std::string>({"x", "ac"}), &listener);
-  EXPECT_EQ(
-      "whose element at {0} matches, whose element #0 doesn't match,\n"
-      "and whose element at {1} matches, whose element #1 doesn't match",
-      listener.str());
+  EXPECT_THAT(listener.str(),
+              MatchesRegex("whose element at \\{0\\} matches, .*\\n"
+                           "and whose element at \\{1\\} matches, .*"));
 }
 
 TEST(MatchesArrayTest, ExplainElementMismatchExplanation) {
   ::testing::StringMatchResultListener listener;
   ::testing::ExplainMatchResult(
       MatchesScalarArray<std::string>(::testing::ElementsAre('a', 'b')),
       MakeScalarArray<std::string>("ac"), &listener);
-  EXPECT_EQ("whose element at {} doesn't match, whose element #1 doesn't match",
-            listener.str());
+  EXPECT_THAT(listener.str(),
+              MatchesRegex("whose element at \\{\\} doesn't match.*"));
 }
 
 TEST(MatchesArrayTest, Matches) {