ctest: Display test labels in failure summary

In a complex test environment, there may be a desire to add a test
property label to indicate context. Here is one such example:

    set_property(TEST mygoofytest PROPERTY LABELS might-fail-on-config-change)

Upon looking at the failed test summary, one can quickly decide whether
the failure might be expected or not.

    198 - mygoofytest (Failed)                might-fail-on-config-change

Source/CTest/cmCTestTestHandler.cxx

@@ -702,13 +702,23 @@ void cmCTestTestHandler::LogFailedTests(const std::vector<std::string>& failed,
         if (this->GetTestStatus(ft) == "Not Run") {
           testColor = cmCTest::Color::YELLOW;
         }
+        std::string ft_name_and_status =
+          cmStrCat(ft.Name, " (", this->GetTestStatus(ft), ")");
+        std::string labels;
+        const cmCTestTestProperties& p = *ft.Properties;
+        if (!p.Labels.empty()) {
+          static size_t const maxLen = 50;
+          size_t const ns = ft_name_and_status.size() >= maxLen
+            ? 1
+            : maxLen - ft_name_and_status.size();
+          labels = cmStrCat(std::string(ns, ' '), cmJoin(p.Labels, " "));
+        }
         cmCTestLog(
           this->CTest, HANDLER_OUTPUT,
           "\t" << this->CTest->GetColorCode(testColor) << std::setw(3)
-               << ft.TestCount << " - " << ft.Name << " ("
+               << ft.TestCount << " - " << ft_name_and_status
-               << this->GetTestStatus(ft) << ")"
                << this->CTest->GetColorCode(cmCTest::Color::CLEAR_COLOR)
-               << std::endl);
+               << labels << std::endl);
       }
     }
   }

Tests/RunCMake/CTestCommandLine/FailureLabels-result.txt

@@ -0,0 +1 @@
+8

Tests/RunCMake/CTestCommandLine/FailureLabels-stderr.txt

@@ -0,0 +1 @@
+Errors while running CTest

Tests/RunCMake/CTestCommandLine/FailureLabels-stdout.txt

@@ -0,0 +1,4 @@
+The following tests FAILED:
+[	 ]+1 - ShortName \(Failed\)                                Label1 Label2
+[	 ]+2 - LongerName \(Failed\)                               Label3
+[	 ]+3 - Long_Test_Name_That_Is_Over_Fifty_Characters_In_Length \(Failed\) Label4

Tests/RunCMake/CTestCommandLine/RunCMakeTest.cmake

@@ -7,6 +7,22 @@ set(ENV{no_proxy} "$ENV{no_proxy},badhostname.invalid")
 
 set(RunCMake_TEST_TIMEOUT 60)
 
+block()
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/FailureLabels)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+  file(WRITE "${RunCMake_TEST_BINARY_DIR}/CTestTestfile.cmake" "
+add_test(ShortName \"${CMAKE_COMMAND}\" -E false)
+set_tests_properties(ShortName PROPERTIES LABELS \"Label1;Label2\")
+add_test(LongerName \"${CMAKE_COMMAND}\" -E false)
+set_tests_properties(LongerName PROPERTIES LABELS \"Label3\")
+add_test(Long_Test_Name_That_Is_Over_Fifty_Characters_In_Length \"${CMAKE_COMMAND}\" -E false)
+set_tests_properties(Long_Test_Name_That_Is_Over_Fifty_Characters_In_Length PROPERTIES LABELS \"Label4\")
+")
+  run_cmake_command(FailureLabels ${CMAKE_CTEST_COMMAND})
+endblock()
+
 run_cmake_command(repeat-opt-bad1
   ${CMAKE_CTEST_COMMAND} --repeat until-pass
   )