Test output expectations should fail if the process has prematurely exited.

expect.go

@@ -86,7 +86,7 @@ func (tt *TermTest) ExpectCustom(consumer consumer, opts ...SetExpectOpt) (rerr
 		return fmt.Errorf("could not create expect options: %w", err)
 	}
 
-	cons, err := tt.outputProducer.addConsumer(consumer, expectOpts.ToConsumerOpts()...)
+	cons, err := tt.outputProducer.addConsumer(tt, consumer, expectOpts.ToConsumerOpts()...)
 	if err != nil {
 		return fmt.Errorf("could not add consumer: %w", err)
 	}
@@ -180,11 +180,11 @@ func (tt *TermTest) expectExitCode(exitCode int, match bool, opts ...SetExpectOp
 	select {
 	case <-time.After(timeoutV):
 		return fmt.Errorf("after %s: %w", timeoutV, TimeoutError)
-	case err := <-waitChan(tt.cmd.Wait):
-		if err != nil && (tt.cmd.ProcessState == nil || tt.cmd.ProcessState.ExitCode() == 0) {
-			return fmt.Errorf("cmd wait failed: %w", err)
+	case state := <-tt.Exited(false): // do not wait for unread output since it's not read by this select{}
+		if state.Err != nil && (state.ProcessState == nil || state.ProcessState.ExitCode() == 0) {
+			return fmt.Errorf("cmd wait failed: %w", state.Err)
 		}
-		if err := tt.assertExitCode(tt.cmd.ProcessState.ExitCode(), exitCode, match); err != nil {
+		if err := tt.assertExitCode(state.ProcessState.ExitCode(), exitCode, match); err != nil {
 			return err
 		}
 	}

helpers.go

@@ -24,19 +24,19 @@ type cmdExit struct {
 }
 
 // waitForCmdExit turns process.wait() into a channel so that it can be used within a select{} statement
-func waitForCmdExit(cmd *exec.Cmd) chan cmdExit {
-	exit := make(chan cmdExit, 1)
+func waitForCmdExit(cmd *exec.Cmd) chan *cmdExit {
+	exit := make(chan *cmdExit, 1)
 	go func() {
 		err := cmd.Wait()
-		exit <- cmdExit{ProcessState: cmd.ProcessState, Err: err}
+		exit <- &cmdExit{ProcessState: cmd.ProcessState, Err: err}
 	}()
 	return exit
 }
 
 func waitChan[T any](wait func() T) chan T {
 	done := make(chan T)
 	go func() {
-		wait()
+		done <- wait()
 		close(done)
 	}()
 	return done

outputconsumer.go

@@ -15,6 +15,7 @@ type outputConsumer struct {
 	opts     *OutputConsumerOpts
 	isalive  bool
 	mutex    *sync.Mutex
+	tt       *TermTest
 }
 
 type OutputConsumerOpts struct {
@@ -36,7 +37,7 @@ func OptsConsTimeout(timeout time.Duration) func(o *OutputConsumerOpts) {
 	}
 }
 
-func newOutputConsumer(consume consumer, opts ...SetConsOpt) *outputConsumer {
+func newOutputConsumer(tt *TermTest, consume consumer, opts ...SetConsOpt) *outputConsumer {
 	oc := &outputConsumer{
 		consume: consume,
 		opts: &OutputConsumerOpts{
@@ -46,6 +47,7 @@ func newOutputConsumer(consume consumer, opts ...SetConsOpt) *outputConsumer {
 		waiter:  make(chan error, 1),
 		isalive: true,
 		mutex:   &sync.Mutex{},
+		tt:      tt,
 	}
 
 	for _, optSetter := range opts {
@@ -101,5 +103,11 @@ func (e *outputConsumer) wait() error {
 		e.mutex.Lock()
 		e.opts.Logger.Println("Encountered timeout")
 		return fmt.Errorf("after %s: %w", e.opts.Timeout, TimeoutError)
+	case state := <-e.tt.Exited(true): // allow for output to be read first by first case in this select{}
+		e.mutex.Lock()
+		if state.Err != nil {
+			e.opts.Logger.Println("Encountered error waiting for process to exit: %s\n", state.Err.Error())
+		}
+		return fmt.Errorf("process exited (status: %d)", state.ProcessState.ExitCode())
 	}
 }

outputproducer.go

@@ -238,12 +238,12 @@ func (o *outputProducer) flushConsumers() error {
 	return nil
 }
 
-func (o *outputProducer) addConsumer(consume consumer, opts ...SetConsOpt) (*outputConsumer, error) {
+func (o *outputProducer) addConsumer(tt *TermTest, consume consumer, opts ...SetConsOpt) (*outputConsumer, error) {
 	o.opts.Logger.Printf("adding consumer")
 	defer o.opts.Logger.Printf("added consumer")
 
 	opts = append(opts, OptConsInherit(o.opts))
-	listener := newOutputConsumer(consume, opts...)
+	listener := newOutputConsumer(tt, consume, opts...)
 	o.consumers = append(o.consumers, listener)
 
 	if err := o.flushConsumers(); err != nil {

termtest.go

@@ -24,6 +24,7 @@ type TermTest struct {
 	outputProducer *outputProducer
 	listenError    chan error
 	opts           *Opts
+	exited         *cmdExit
 }
 
 type ErrorHandler func(*TermTest, error) error
@@ -50,6 +51,9 @@ type SetOpt func(o *Opts) error
 const DefaultCols = 140
 const DefaultRows = 10
 
+var processExitPollInterval = 10 * time.Millisecond
+var processExitExtraWait = 500 * time.Millisecond
+
 func NewOpts() *Opts {
 	return &Opts{
 		Logger: VoidLogger,
@@ -234,6 +238,10 @@ func (tt *TermTest) start() (rerr error) {
 	}()
 	wg.Wait()
 
+	go func() {
+		tt.exited = <-waitForCmdExit(tt.cmd)
+	}()
+
 	return nil
 }
 
@@ -316,6 +324,28 @@ func (tt *TermTest) SendCtrlC() {
 	tt.Send(string([]byte{0x03})) // 0x03 is ASCII character for ^C
 }
 
+// Exited returns a channel that sends the given termtest's command cmdExit info when available.
+// This can be used within a select{} statement.
+// If waitExtra is given, waits a little bit before sending cmdExit info. This allows any fellow
+// switch cases with output consumers to handle unprocessed stdout. If there are no such cases
+// (e.g. ExpectExit(), where we want to catch an exit ASAP), waitExtra should be false.
+func (tt *TermTest) Exited(waitExtra bool) chan *cmdExit {
+	return waitChan(func() *cmdExit {
+		ticker := time.NewTicker(processExitPollInterval)
+		for {
+			select {
+			case <-ticker.C:
+				if tt.exited != nil {
+					if waitExtra { // allow sibling output consumer cases to handle their output
+						time.Sleep(processExitExtraWait)
+					}
+					return tt.exited
+				}
+			}
+		}
+	})
+}
+
 func (tt *TermTest) errorHandler(rerr *error) {
 	err := *rerr
 	if err == nil {