Add IgnoreNonJSONOutputLines, --ignore-non-json-output-lines

README.md

@@ -220,11 +220,17 @@ gotestsum -- -coverprofile=cover.out ./...
 gotestsum --raw-command -- ./scripts/run_tests.sh
 ```
 
-Note: when using `--raw-command` you must ensure that the stdout produced by
-the script only contains the `test2json` output. Any stderr produced by the script
-will be considered an error (this behaviour is necessary because package build errors
-are only reported by writting to stderr, not the `test2json` stdout). Any stderr
-produced by tests is not considered an error (it will be in the `test2json` stdout).
+Note: when using `--raw-command`, the script must follow a few rules about
+stdout and stderr output:
+
+* The stdout produced by the script must only contain the `test2json` output, or
+  `gotestsum` will fail. If it isn't possible to change the script to avoid
+  non-JSON output, you can use `--ignore-non-json-output-lines` to ignore
+  non-JSON lines and write them to `gotestsum`'s stderr instead.
+* Any stderr produced by the script will be considered an error (this behaviour
+  is necessary because package build errors are only reported by writting to
+  stderr, not the `test2json` stdout). Any stderr produced by tests is not
+  considered an error (it will be in the `test2json` stdout).
 
 **Example: using `TEST_DIRECTORY`**
 ```

cmd/main.go

@@ -59,6 +59,9 @@ func setupFlags(name string) (*pflag.FlagSet, *options) {
 		"print format of test input")
 	flags.BoolVar(&opts.rawCommand, "raw-command", false,
 		"don't prepend 'go test -json' to the 'go test' command")
+	flags.BoolVar(&opts.ignoreNonJSONOutputLines, "ignore-non-json-output-lines", false,
+		"write non-JSON 'go test' output lines to stderr instead of failing")
+	flags.Lookup("ignore-non-json-output-lines").Hidden = true
 	flags.StringVar(&opts.jsonFile, "jsonfile",
 		lookEnvWithDefault("GOTESTSUM_JSONFILE", ""),
 		"write all TestEvents to file")
@@ -138,6 +141,7 @@ type options struct {
 	format                       string
 	debug                        bool
 	rawCommand                   bool
+	ignoreNonJSONOutputLines     bool
 	jsonFile                     string
 	junitFile                    string
 	postRunHookCmd               *commandValue
@@ -194,10 +198,11 @@ func run(opts *options) error {
 	}
 	defer handler.Close() // nolint: errcheck
 	cfg := testjson.ScanConfig{
-		Stdout:  goTestProc.stdout,
-		Stderr:  goTestProc.stderr,
-		Handler: handler,
-		Stop:    cancel,
+		Stdout:                   goTestProc.stdout,
+		Stderr:                   goTestProc.stderr,
+		Handler:                  handler,
+		Stop:                     cancel,
+		IgnoreNonJSONOutputLines: opts.ignoreNonJSONOutputLines,
 	}
 	exec, err := testjson.ScanTestOutput(cfg)
 	if err != nil {

testjson/execution.go

@@ -590,6 +590,9 @@ type ScanConfig struct {
 	Execution *Execution
 	// Stop is called when ScanTestOutput fails during a scan.
 	Stop func()
+	// IgnoreNonJSONOutputLines causes ScanTestOutput to ignore non-JSON lines received from
+	// the Stdout reader. Instead of causing an error, the lines will be sent to Handler.Err.
+	IgnoreNonJSONOutputLines bool
 }
 
 // EventHandler is called by ScanTestOutput for each event and write to stderr.
@@ -662,6 +665,11 @@ func readStdout(config ScanConfig, execution *Execution) error {
 			config.Handler.Err(errBadEvent.Error() + ": " + scanner.Text())
 			continue
 		case err != nil:
+			if config.IgnoreNonJSONOutputLines {
+				// nolint: errcheck
+				config.Handler.Err(string(raw))
+				continue
+			}
 			return errors.Wrapf(err, "failed to parse test output: %s", string(raw))
 		}
 

testjson/execution_test.go

@@ -205,8 +205,37 @@ func TestScanOutput_WithMissingEvents(t *testing.T) {
 	assert.DeepEqual(t, expected, handler.events[start:], cmpTestEventShallow)
 }
 
+func TestScanOutput_WithNonJSONLines(t *testing.T) {
+	source := golden.Get(t, "go-test-json-with-nonjson-stdout.out")
+	nonJSONLine := "|||This line is not valid test2json output.|||"
+
+	// Test that when we ignore non-JSON lines, scanning completes, and test
+	// that when we don't ignore non-JSON lines, scanning fails.
+	for _, ignore := range []bool{true, false} {
+		t.Run(fmt.Sprintf("ignore-non-json=%v", ignore), func(t *testing.T) {
+			handler := &captureHandler{}
+			cfg := ScanConfig{
+				Stdout:                   bytes.NewReader(source),
+				Handler:                  handler,
+				IgnoreNonJSONOutputLines: ignore,
+			}
+			_, err := ScanTestOutput(cfg)
+			if ignore {
+				assert.DeepEqual(t, handler.errs, []string{nonJSONLine})
+				assert.NilError(t, err)
+				return
+			}
+			assert.DeepEqual(t, handler.errs, []string{}, cmpopts.EquateEmpty())
+			expected := "failed to parse test output: " +
+				nonJSONLine + ": invalid character '|' looking for beginning of value"
+			assert.Error(t, err, expected)
+		})
+	}
+}
+
 type captureHandler struct {
 	events []TestEvent
+	errs   []string
 }
 
 func (s *captureHandler) Event(event TestEvent, _ *Execution) error {
@@ -215,5 +244,6 @@ func (s *captureHandler) Event(event TestEvent, _ *Execution) error {
 }
 
 func (s *captureHandler) Err(text string) error {
+	s.errs = append(s.errs, text)
 	return fmt.Errorf(text)
 }

testjson/testdata/go-test-json-with-nonjson-stdout.out

@@ -0,0 +1,8 @@
+{"Time":"2021-05-12T13:53:07.462687619-05:00","Action":"run","Package":"gotest.tools/gotestsum/testjson/internal/good","Test":"TestPassed"}
+|||This line is not valid test2json output.|||
+{"Time":"2021-05-12T13:53:07.46279664-05:00","Action":"output","Package":"gotest.tools/gotestsum/testjson/internal/good","Test":"TestPassed","Output":"=== RUN   TestPassed\n"}
+{"Time":"2021-05-12T13:53:07.462812837-05:00","Action":"output","Package":"gotest.tools/gotestsum/testjson/internal/good","Test":"TestPassed","Output":"--- PASS: TestPassed (0.00s)\n"}
+{"Time":"2021-05-12T13:53:07.462819251-05:00","Action":"pass","Package":"gotest.tools/gotestsum/testjson/internal/good","Test":"TestPassed","Elapsed":0}
+{"Time":"2021-05-12T13:53:07.462825108-05:00","Action":"output","Package":"gotest.tools/gotestsum/testjson/internal/good","Output":"PASS\n"}
+{"Time":"2021-05-12T13:53:07.462848483-05:00","Action":"output","Package":"gotest.tools/gotestsum/testjson/internal/good","Output":"ok  \tgotest.tools/gotestsum/testjson/internal/good\t0.001s\n"}
+{"Time":"2021-05-12T13:53:07.46309146-05:00","Action":"pass","Package":"gotest.tools/gotestsum/testjson/internal/good","Elapsed":0.001}