Add start time timestamps to <testcase>/Run data in JUnit XML outpu…

…t from `terraform test` (#36295)

* Record metadata about the start timestamp for a Run/test case

* Add RFC3339 format timestamp attributes to `<testcase>` elements in JUnit XML output

* Ensure timestamps are saved as and rendered as UTC timestamps

internal/backend/local/test.go

@@ -355,7 +355,7 @@ func (runner *TestFileRunner) Test(file *moduletest.File) {
 			}
 		}
 
-		startTime := time.Now()
+		startTime := time.Now().UTC()
 		state, updatedState := runner.run(run, file, runner.RelevantStates[key].State, config)
 		runDuration := time.Since(startTime)
 		if updatedState {
@@ -370,6 +370,7 @@ func (runner *TestFileRunner) Test(file *moduletest.File) {
 		// If we got far enough to actually execute the run then we'll give
 		// the view some additional metadata about the execution.
 		run.ExecutionMeta = &moduletest.RunExecutionMeta{
+			Start:    startTime,
 			Duration: runDuration,
 		}
 		runner.Suite.View.Run(run, file, moduletest.Complete, 0)

internal/command/views/test.go

@@ -898,7 +898,8 @@ func junitXMLTestReport(suite *moduletest.Suite) ([]byte, error) {
 				// "not known", and thus omit that case. (In practice many
 				// JUnit XML consumers treat the absense of this attribute
 				// as zero anyway.)
-				RunTime float64 `xml:"time,attr,omitempty"`
+				RunTime   float64 `xml:"time,attr,omitempty"`
+				Timestamp string  `xml:"timestamp,attr,omitempty"`
 			}
 
 			testCase := TestCase{
@@ -913,6 +914,7 @@ func junitXMLTestReport(suite *moduletest.Suite) ([]byte, error) {
 			}
 			if execMeta := run.ExecutionMeta; execMeta != nil {
 				testCase.RunTime = execMeta.Duration.Seconds()
+				testCase.Timestamp = execMeta.StartTimestamp()
 			}
 			switch run.Status {
 			case moduletest.Skip:

internal/moduletest/run.go

@@ -43,9 +43,20 @@ type Run struct {
 }
 
 type RunExecutionMeta struct {
+	Start    time.Time
 	Duration time.Duration
 }
 
+// StartTimestamp returns the start time metadata as a timestamp formatted as YYYY-MM-DDTHH:MM:SSZ.
+// Times are converted to UTC, if they aren't already.
+// If the start time is unset an empty string is returned.
+func (m *RunExecutionMeta) StartTimestamp() string {
+	if m.Start.IsZero() {
+		return ""
+	}
+	return m.Start.UTC().Format(time.RFC3339)
+}
+
 // Verbose is a utility struct that holds all the information required for a run
 // to render the results verbosely.
 //