Add post-run-command hook

Pass environment variables with some summary info

handler.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/exec"
 
 	"github.com/pkg/errors"
 	"gotest.tools/gotestsum/internal/junitxml"
@@ -86,3 +87,24 @@ func writeJUnitFile(opts *options, execution *testjson.Execution) error {
 		FormatTestCaseClassname: opts.junitTestCaseClassnameFormat.Value(),
 	})
 }
+
+func postRunHook(opts *options, execution *testjson.Execution) error {
+	if len(opts.postRunHookCmd) == 0 {
+		return nil
+	}
+
+	cmd := exec.Command(opts.postRunHookCmd[0], opts.postRunHookCmd[1:]...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.Env = append(
+		os.Environ(),
+		"GOTESTSUM_JSONFILE="+opts.jsonFile,
+		"GOTESTSUM_JUNITFILE"+opts.junitFile,
+		fmt.Sprintf("TESTS_TOTAL=%d", execution.Total()),
+		fmt.Sprintf("TESTS_FAILED=%d", len(execution.Failed())),
+		fmt.Sprintf("TESTS_SKIPPED=%d", len(execution.Skipped())),
+		fmt.Sprintf("TESTS_ERRORS=%d", len(execution.Errors())),
+	)
+	// TODO: send a more detailed report to stdin?
+	return cmd.Run()
+}

main.go

@@ -109,6 +109,8 @@ Formats:
 		"format the testsuite name field as: "+junitFieldFormatValues)
 	flags.Var(opts.junitTestCaseClassnameFormat, "junitfile-testcase-classname",
 		"format the testcase classname field as: "+junitFieldFormatValues)
+	flags.StringSliceVar(&opts.postRunHookCmd, "post-run-command",
+		nil, "run this command once the tests have completed")
 	flags.BoolVar(&opts.version, "version", false, "show version and exit")
 	return flags, opts
 }
@@ -127,6 +129,7 @@ type options struct {
 	rawCommand                   bool
 	jsonFile                     string
 	junitFile                    string
+	postRunHookCmd               []string
 	noColor                      bool
 	noSummary                    *noSummaryValue
 	junitTestSuiteNameFormat     *junitFieldFormatValue
@@ -169,6 +172,9 @@ func run(opts *options) error {
 	if err := writeJUnitFile(opts, exec); err != nil {
 		return err
 	}
+	if err := postRunHook(opts, exec); err != nil {
+		return err
+	}
 	return goTestProc.cmd.Wait()
 }