Add function in MatchOutputCodeTest to find occurrence of a string

src/tests/test_utils/compiler_test.cpp

@@ -140,14 +140,19 @@ bool MatchOutputCodeTest::compileWithSettings(ShShaderOutput output,
 
 bool MatchOutputCodeTest::foundInCode(ShShaderOutput output, const char *stringToFind) const
 {
+    return findInCode(output, stringToFind) != std::string::npos;
+}
+
+size_t MatchOutputCodeTest::findInCode(ShShaderOutput output, const char *stringToFind) const
+{
     const auto code = mOutputCode.find(output);
     EXPECT_NE(mOutputCode.end(), code);
     if (code == mOutputCode.end())
     {
-        return false;
+        return std::string::npos;
     }
 
-    return code->second.find(stringToFind) != std::string::npos;
+    return code->second.find(stringToFind);
 }
 
 bool MatchOutputCodeTest::foundInCode(ShShaderOutput output,

src/tests/test_utils/compiler_test.h

@@ -64,6 +64,9 @@ class MatchOutputCodeTest : public testing::Test
     }
 
     bool foundInCode(ShShaderOutput output, const char *stringToFind) const;
+    // Returns the position of the first character of the first match in the translated output
+    // source. If no matches are found, then string::npos is returned.
+    size_t findInCode(ShShaderOutput output, const char *stringToFind) const;
 
     // Test that the string occurs for exactly expectedOccurrences times
     bool foundInCode(ShShaderOutput output,