Add the time unit to elapsed time duration

README.md

@@ -139,8 +139,8 @@ test run has completed. The binary will be run with the following environment
 variables set:
 
 ```
-GOTESTSUM_ELAPSED       # test time elapsed, in seconds
-GOTESTSUM_FORMAT        # gotestsum format (ex: short)
+GOTESTSUM_ELAPSED       # test run time in seconds (ex: 2.45s)
+GOTESTSUM_FORMAT        # gotestsum format (ex: pkgname)
 GOTESTSUM_JSONFILE      # path to the jsonfile, empty if no file path was given
 GOTESTSUM_JUNITFILE     # path to the junit.xml file, empty if no file path was given
 TESTS_ERRORS            # number of errors

cmd/handler.go

@@ -170,7 +170,7 @@ func postRunHook(opts *options, execution *testjson.Execution) error {
 		"GOTESTSUM_JSONFILE="+opts.jsonFile,
 		"GOTESTSUM_JSONFILE_TIMING_EVENTS="+opts.jsonFileTimingEvents,
 		"GOTESTSUM_JUNITFILE="+opts.junitFile,
-		fmt.Sprintf("GOTESTSUM_ELAPSED=%.3f", execution.Elapsed().Seconds()),
+		fmt.Sprintf("GOTESTSUM_ELAPSED=%.3fs", execution.Elapsed().Seconds()),
 		fmt.Sprintf("TESTS_TOTAL=%d", execution.Total()),
 		fmt.Sprintf("TESTS_FAILED=%d", len(execution.Failed())),
 		fmt.Sprintf("TESTS_SKIPPED=%d", len(execution.Skipped())),

cmd/handler_test.go

@@ -39,9 +39,10 @@ func TestPostRunHook(t *testing.T) {
 	assert.NilError(t, err)
 
 	actual := text.ProcessLines(t, buf, func(line string) string {
-		if strings.HasPrefix(line, "GOTESTSUM_ELAPSED=0.0") {
+		if strings.HasPrefix(line, "GOTESTSUM_ELAPSED=0.0") &&
+			strings.HasSuffix(line, "s") {
 			i := strings.Index(line, "=")
-			return line[:i] + "=0.000"
+			return line[:i] + "=0.000s"
 		}
 		return line
 	})

cmd/testdata/post-run-hook-expected

@@ -1,4 +1,4 @@
-GOTESTSUM_ELAPSED=0.000
+GOTESTSUM_ELAPSED=0.000s
 GOTESTSUM_FORMAT=short
 GOTESTSUM_JSONFILE=events.json
 GOTESTSUM_JSONFILE_TIMING_EVENTS=timing.json