Clean up stoppable

stoppable/cleanup.go

@@ -16,74 +16,78 @@ import (
 	"time"
 )
 
+const nameTag = " with cleanup"
+
+type CleanFunc func(duration time.Duration) error
+
 // Cleanup wraps any stoppable and runs a callback after to stop for cleanup
 // behavior. The cleanup is run under the remainder of the timeout but will not
 // be canceled if the timeout runs out. The cleanup function does not run if the
 // thread does not stop.
 type Cleanup struct {
 	stop Stoppable
-	// the clean function receives how long it has to run before the timeout,
-	// this is nto expected to be used in most cases
-	clean   func(duration time.Duration) error
+	// clean receives how long it has to run before the timeout, this is not
+	// expected to be used in most cases
+	clean   CleanFunc
 	running uint32
 	once    sync.Once
 }
 
-// NewCleanup creates a new Cleanup from the passed stoppable and function.
-func NewCleanup(stop Stoppable, clean func(duration time.Duration) error) *Cleanup {
+// NewCleanup creates a new Cleanup from the passed in stoppable and clean
+// function.
+func NewCleanup(stop Stoppable, clean CleanFunc) *Cleanup {
 	return &Cleanup{
 		stop:    stop,
 		clean:   clean,
-		running: 0,
+		running: stopped,
 	}
 }
 
 // IsRunning returns true if the thread is still running and its cleanup has
 // completed.
 func (c *Cleanup) IsRunning() bool {
-	return atomic.LoadUint32(&c.running) == 1
+	return atomic.LoadUint32(&c.running) == running
 }
 
 // Name returns the name of the stoppable denoting it has cleanup.
 func (c *Cleanup) Name() string {
-	return c.stop.Name() + " with cleanup"
+	return c.stop.Name() + nameTag
 }
 
-// Close stops the contained stoppable and runs the cleanup function after. The
-// cleanup function does not run if the thread does not stop.
+// Close stops the wrapped stoppable and after, runs the cleanup function. The
+// cleanup function does not run if the thread fails to stop.
 func (c *Cleanup) Close(timeout time.Duration) error {
 	var err error
 
 	c.once.Do(
 		func() {
-			defer atomic.StoreUint32(&c.running, 0)
+			defer atomic.StoreUint32(&c.running, stopped)
 			start := netTime.Now()
 
-			// Run the stoppable
+			// Close each stoppable
 			if err := c.stop.Close(timeout); err != nil {
-				err = errors.WithMessagef(err, "Cleanup for %s not executed",
+				err = errors.WithMessagef(err, "Cleanup not executed for %s",
 					c.stop.Name())
 				return
 			}
 
 			// Run the cleanup function with the remaining time as a timeout
-			elapsed := time.Since(start)
+			elapsed := netTime.Now().Sub(start)
 
 			complete := make(chan error, 1)
 			go func() {
 				complete <- c.clean(elapsed)
 			}()
 
-			timer := time.NewTimer(elapsed)
-
 			select {
 			case err := <-complete:
 				if err != nil {
 					err = errors.WithMessagef(err, "Cleanup for %s failed",
 						c.stop.Name())
 				}
-			case <-timer.C:
-				err = errors.Errorf("Clean up for %s timeout", c.stop.Name())
+			case <-time.NewTimer(elapsed).C:
+				err = errors.Errorf("Clean up for %s timed out after %s",
+					c.stop.Name(), elapsed)
 			}
 		})
 

stoppable/cleanup_test.go

@@ -11,52 +11,68 @@ import (
 	"testing"
 )
 
-// Tests happy path of NewCleanup().
+// Tests that NewCleanup returns a Cleanup that is stopped with the given
+// Stoppable.
 func TestNewCleanup(t *testing.T) {
-	single := NewSingle("test name")
+	single := NewSingle("testSingle")
 	cleanup := NewCleanup(single, single.Close)
 
-	if cleanup.stop != single || cleanup.running != 0 {
-		t.Errorf("NewCleanup() returned Single with incorrect values."+
-			"\n\texpected:  stop: %v  running: %d\n\treceived:  stop: %v  running: %d",
-			single, cleanup.stop, 0, cleanup.running)
+	if cleanup.stop != single {
+		t.Errorf("NewCleanup returned cleanup with incorrect Stoppable."+
+			"\nexpected: %+v\nreceived: %+v", single, cleanup.stop)
+	}
+
+	if cleanup.running != stopped {
+		t.Errorf("NewMulti returned Multi with incorrect running."+
+			"\nexpected: %d\nreceived: %d", stopped, cleanup.running)
 	}
 }
 
-// Tests happy path of Cleanup.IsRunning().
+// Tests that Cleanup.IsRunning returns the expected value when the Cleanup is
+// marked as both running and not running.
 func TestCleanup_IsRunning(t *testing.T) {
-	single := NewSingle("test name")
+	single := NewSingle("threadName")
 	cleanup := NewCleanup(single, single.Close)
 
 	if cleanup.IsRunning() {
-		t.Errorf("IsRunning() returned false when it should be running.")
+		t.Errorf("IsRunning returned the wrong value when running."+
+			"\nexpected: %t\nreceived: %t", true, cleanup.IsRunning())
 	}
 
-	cleanup.running = 1
-	if !cleanup.IsRunning() {
-		t.Errorf("IsRunning() returned true when it should not be running.")
+	cleanup.running = running
+	if !single.IsRunning() {
+		t.Errorf("IsRunning returned the wrong value when running."+
+			"\nexpected: %t\nreceived: %t", false, single.IsRunning())
 	}
 }
 
-// Tests happy path of Cleanup.Name().
+// Unit test of Cleanup.Name.
 func TestCleanup_Name(t *testing.T) {
-	name := "test name"
+	name := "threadName"
 	single := NewSingle(name)
 	cleanup := NewCleanup(single, single.Close)
 
-	if name+" with cleanup" != cleanup.Name() {
-		t.Errorf("Name() returned the incorrect string."+
-			"\n\texpected: %s\n\treceived: %s", name+" with cleanup", cleanup.Name())
+	if name+nameTag != cleanup.Name() {
+		t.Errorf("Name did not return the expected name."+
+			"\nexpected: %s\nreceived: %s", name+nameTag, cleanup.Name())
 	}
 }
 
 // Tests happy path of Cleanup.Close().
 func TestCleanup_Close(t *testing.T) {
-	single := NewSingle("test name")
+	single := NewSingle("threadName")
 	cleanup := NewCleanup(single, single.Close)
 
+	// go func() {
+	// 	select {
+	// 	case <-time.NewTimer(10 * time.Millisecond).C:
+	// 		t.Error("Timed out waiting for quit channel.")
+	// 	case <-single.Quit():
+	// 	}
+	// }()
+
 	err := cleanup.Close(0)
 	if err != nil {
-		t.Errorf("Close() returned an error: %v", err)
+		t.Errorf("Close() returned an error: %+v", err)
 	}
 }

stoppable/multi.go

@@ -8,14 +8,17 @@
 package stoppable
 
 import (
-	"fmt"
 	"github.com/pkg/errors"
 	jww "github.com/spf13/jwalterweatherman"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
 )
 
+// Error message.
+const closeMultiErr = "MultiStopper %s failed to close %d/%d stoppers"
+
 type Multi struct {
 	stoppables []Stoppable
 	name       string
@@ -24,17 +27,17 @@ type Multi struct {
 	once       sync.Once
 }
 
-// NewMulti returns a new multi stoppable.
+// NewMulti returns a new multi Stoppable.
 func NewMulti(name string) *Multi {
 	return &Multi{
 		name:    name,
-		running: 1,
+		running: running,
 	}
 }
 
-// IsRunning returns true if the thread is still running.
+// IsRunning returns true if stoppable is marked as running.
 func (m *Multi) IsRunning() bool {
-	return atomic.LoadUint32(&m.running) == 1
+	return atomic.LoadUint32(&m.running) == running
 }
 
 // Add adds the given stoppable to the list of stoppables.
@@ -44,21 +47,18 @@ func (m *Multi) Add(stoppable Stoppable) {
 	m.mux.Unlock()
 }
 
-// Name returns the name of the multi stoppable and the names of all stoppables
+// Name returns the name of the Multi Stoppable and the names of all stoppables
 // it contains.
 func (m *Multi) Name() string {
 	m.mux.RLock()
-	names := m.name + ": {"
-	for _, s := range m.stoppables {
-		names += s.Name() + ", "
-	}
-	if len(m.stoppables) > 0 {
-		names = names[:len(names)-2]
+	defer m.mux.RUnlock()
+
+	names := make([]string, len(m.stoppables))
+	for i, s := range m.stoppables {
+		names[i] = s.Name()
 	}
-	names += "}"
-	m.mux.RUnlock()
 
-	return names
+	return m.name + ": {" + strings.Join(names, ", ") + "}"
 }
 
 // Close closes all child stoppers. It does not return their errors and assumes
@@ -67,10 +67,10 @@ func (m *Multi) Close(timeout time.Duration) error {
 	var err error
 	m.once.Do(
 		func() {
-			atomic.StoreUint32(&m.running, 0)
+			atomic.StoreUint32(&m.running, stopped)
 
-			numErrors := uint32(0)
-			wg := &sync.WaitGroup{}
+			var numErrors uint32
+			var wg sync.WaitGroup
 
 			m.mux.Lock()
 			for _, stoppable := range m.stoppables {
@@ -87,10 +87,9 @@ func (m *Multi) Close(timeout time.Duration) error {
 			wg.Wait()
 
 			if numErrors > 0 {
-				errStr := fmt.Sprintf("MultiStopper %s failed to close "+
-					"%v/%v stoppers", m.name, numErrors, len(m.stoppables))
-				jww.ERROR.Println(errStr)
-				err = errors.New(errStr)
+				err = errors.Errorf(
+					closeMultiErr, m.name, numErrors, len(m.stoppables))
+				jww.ERROR.Print(err.Error())
 			}
 		})
 

stoppable/multi_test.go

@@ -8,107 +8,140 @@
 package stoppable
 
 import (
+	"fmt"
 	"reflect"
+	"strconv"
+	"strings"
 	"testing"
 	"time"
 )
 
-// Tests happy path of NewMulti().
+// Tests that NewMulti returns a Multi that is running with the given name.
 func TestNewMulti(t *testing.T) {
-	name := "test name"
+	name := "testMulti"
 	multi := NewMulti(name)
 
-	if multi.name != name || multi.running != 1 {
-		t.Errorf("NewMulti() returned Multi with incorrect values."+
-			"\n\texpected:  name: %s  running: %d\n\treceived:  name: %s  running: %d",
-			name, 1, multi.name, multi.running)
+	if multi.name != name {
+		t.Errorf("NewMulti returned Multi with incorrect name."+
+			"\nexpected: %s\nreceived: %s", name, multi.name)
+	}
+
+	if multi.running != running {
+		t.Errorf("NewMulti returned Multi with incorrect running."+
+			"\nexpected: %d\nreceived: %d", running, multi.running)
 	}
 }
 
-// Tests happy path of Multi.IsRunning().
+// Tests that Multi.IsRunning returns the expected value when the Multi is
+// marked as both running and not running.
 func TestMulti_IsRunning(t *testing.T) {
-	multi := NewMulti("name")
+	multi := NewMulti("testMulti")
 
 	if !multi.IsRunning() {
-		t.Errorf("IsRunning() returned false when it should be running.")
+		t.Errorf("IsRunning returned the wrong value when running."+
+			"\nexpected: %t\nreceived: %t", true, multi.IsRunning())
 	}
 
-	multi.running = 0
+	multi.running = stopped
 	if multi.IsRunning() {
-		t.Errorf("IsRunning() returned true when it should not be running.")
+		t.Errorf("IsRunning returned the wrong value when not running."+
+			"\nexpected: %t\nreceived: %t", false, multi.IsRunning())
 	}
 }
 
-// Tests happy path of Multi.Add().
+// Tests that Multi.Add adds all the stoppables to the list.
 func TestMulti_Add(t *testing.T) {
-	multi := NewMulti("multi name")
-	singles := []*Single{
-		NewSingle("single name 1"),
-		NewSingle("single name 2"),
-		NewSingle("single name 3"),
+	multi := NewMulti("testMulti")
+	expected := []Stoppable{
+		NewSingle("testSingle0"),
+		NewMulti("testMulti0"),
+		NewSingle("testSingle1"),
+		NewMulti("testMulti1"),
 	}
 
-	for _, single := range singles {
-		multi.Add(single)
+	for _, stoppable := range expected {
+		multi.Add(stoppable)
 	}
 
-	for i, single := range singles {
-		if !reflect.DeepEqual(single, multi.stoppables[i]) {
-			t.Errorf("Add() did not add the correct Stoppables."+
-				"\n\texpected: %#v\n\treceived: %#v", single, multi.stoppables[i])
-		}
+	if !reflect.DeepEqual(multi.stoppables, expected) {
+		t.Errorf("Add did not add the correct Stoppables."+
+			"\nexpected: %+v\nreceived: %+v", multi.stoppables, expected)
 	}
 }
 
-// Tests happy path of Multi.Name().
+// Unit test of Multi.Name.
 func TestMulti_Name(t *testing.T) {
-	name := "test name"
+	name := "testMulti"
 	multi := NewMulti(name)
-	singles := []*Single{
-		NewSingle("single name 1"),
-		NewSingle("single name 2"),
-		NewSingle("single name 3"),
+
+	// Add stoppables and created list of their names
+	var nameList []string
+	for i := 0; i < 10; i++ {
+		newName := ""
+		if i%2 == 0 {
+			newName = "single" + strconv.Itoa(i)
+			multi.Add(NewSingle(newName))
+		} else {
+			newMulti := NewMulti("multi" + strconv.Itoa(i))
+			if i != 5 {
+				newMulti.Add(NewMulti("multiA"))
+				newMulti.Add(NewMulti("multiB"))
+			}
+			multi.Add(newMulti)
+			newName = newMulti.Name()
 		}
-	expectedNames := []string{
-		name + ": {}",
-		name + ": {" + singles[0].name + "}",
-		name + ": {" + singles[0].name + ", " + singles[1].name + "}",
-		name + ": {" + singles[0].name + ", " + singles[1].name + ", " + singles[2].name + "}",
+		nameList = append(nameList, newName)
 	}
 
-	for i, single := range singles {
-		if expectedNames[i] != multi.Name() {
-			t.Errorf("Name() returned the incorrect string."+
-				"\n\texpected: %s\n\treceived: %s", expectedNames[0], multi.Name())
+	expected := name + ": {" + strings.Join(nameList, ", ") + "}"
+
+	if multi.Name() != expected {
+		t.Errorf("Name failed to return the expected string."+
+			"\nexpected: %s\nreceived: %s", expected, multi.Name())
 	}
-		multi.Add(single)
+}
+
+// Tests that Multi.Name returns the expected string when it has no stoppables.
+func TestMulti_Name_NoStoppables(t *testing.T) {
+	name := "testMulti"
+	multi := NewMulti(name)
+
+	expected := name + ": {" + "}"
+
+	if multi.Name() != expected {
+		t.Errorf("Name failed to return the expected string."+
+			"\nexpected: %s\nreceived: %s", expected, multi.Name())
 	}
 }
 
-// Tests happy path of Multi.Close().
+// Tests that Multi.Close sends on all Single quit channels.
 func TestMulti_Close(t *testing.T) {
-	// Create new Multi and add Singles to it
-	multi := NewMulti("name")
+	multi := NewMulti("testMulti")
 	singles := []*Single{
-		NewSingle("single name 1"),
-		NewSingle("single name 2"),
-		NewSingle("single name 3"),
+		NewSingle("testSingle0"),
+		NewSingle("testSingle1"),
+		NewSingle("testSingle2"),
+		NewSingle("testSingle3"),
+		NewSingle("testSingle4"),
 	}
-	for _, single := range singles {
+	for _, single := range singles[:3] {
 		multi.Add(single)
 	}
+	subMulti := NewMulti("subMulti")
+	for _, single := range singles[3:] {
+		subMulti.Add(single)
+	}
+	multi.Add(subMulti)
 
-	go func() {
+	for _, single := range singles {
+		go func(single *Single) {
 			select {
-		case <-singles[0].quit:
+			case <-time.NewTimer(5 * time.Millisecond).C:
+				t.Errorf("Single %s failed to quit.", single.Name())
+			case <-single.Quit():
 			}
-		select {
-		case <-singles[1].quit:
+		}(single)
 	}
-		select {
-		case <-singles[2].quit:
-		}
-	}()
 
 	err := multi.Close(5 * time.Millisecond)
 	if err != nil {
@@ -120,3 +153,46 @@ func TestMulti_Close(t *testing.T) {
 		t.Errorf("Close() returned an error: %v", err)
 	}
 }
+
+// Tests that Multi.Close sends on all Single quit channels.
+func TestMulti_Close_Error(t *testing.T) {
+	multi := NewMulti("testMulti")
+	singles := []*Single{
+		NewSingle("testSingle0"),
+		NewSingle("testSingle1"),
+		NewSingle("testSingle2"),
+		NewSingle("testSingle3"),
+		NewSingle("testSingle4"),
+	}
+	for _, single := range singles[:3] {
+		multi.Add(single)
+	}
+	subMulti := NewMulti("subMulti")
+	for _, single := range singles[3:] {
+		subMulti.Add(single)
+	}
+	multi.Add(subMulti)
+
+	for _, single := range singles[:2] {
+		go func(single *Single) {
+			select {
+			case <-time.NewTimer(5 * time.Millisecond).C:
+				t.Errorf("Single %s failed to quit.", single.Name())
+			case <-single.Quit():
+			}
+		}(single)
+	}
+	expectedErr := fmt.Sprintf(closeMultiErr, multi.name, 0, 0)
+	expectedErr = strings.SplitN(expectedErr, " 0/0", 2)[0]
+
+	err := multi.Close(5 * time.Millisecond)
+	if err == nil || !strings.Contains(err.Error(), expectedErr) {
+		t.Errorf("Close() did not return the expected error."+
+			"\nexpected: %s\nreceived: %v", expectedErr, err)
+	}
+
+	err = multi.Close(0)
+	if err != nil {
+		t.Errorf("Close() returned an error: %v", err)
+	}
+}

stoppable/single.go

@@ -15,8 +15,11 @@ import (
 	"time"
 )
 
-// Single allows stopping a single goroutine using a channel.
-// It adheres to the stoppable interface.
+// Error message.
+const closeTimeoutErr = "stopper for %s failed to stop after timeout of %s"
+
+// Single allows stopping a single goroutine using a channel. It adheres to the
+// Stoppable interface.
 type Single struct {
 	name    string
 	quit    chan struct{}
@@ -24,43 +27,44 @@ type Single struct {
 	once    sync.Once
 }
 
-// NewSingle returns a new single stoppable.
+// NewSingle returns a new single Stoppable.
 func NewSingle(name string) *Single {
 	return &Single{
 		name:    name,
 		quit:    make(chan struct{}),
-		running: 1,
+		running: running,
 	}
 }
 
-// IsRunning returns true if the thread is still running.
+// IsRunning returns true if stoppable is marked as running.
 func (s *Single) IsRunning() bool {
-	return atomic.LoadUint32(&s.running) == 1
+	return atomic.LoadUint32(&s.running) == running
 }
 
-// Quit returns the read only channel it will send the stop signal on.
+// Quit returns a receive-only channel that will be triggered when the Stoppable
+// quits.
 func (s *Single) Quit() <-chan struct{} {
 	return s.quit
 }
 
-// Name returns the name of the thread. This is designed to be
+// Name returns the name of the Single Stoppable.
 func (s *Single) Name() string {
 	return s.name
 }
 
-// Close signals the thread to time out and closes if it is still running.
+// Close signals the Single to close via the quit channel. Returns an error if
+// sending on the quit channel times out.
 func (s *Single) Close(timeout time.Duration) error {
 	var err error
 	s.once.Do(func() {
-		timer := time.NewTimer(timeout)
 		select {
-		case <-timer.C:
-			jww.ERROR.Printf("Stopper for %s failed to stop after "+
-				"timeout of %s", s.name, timeout)
-			err = errors.Errorf("%s failed to close", s.name)
+		case <-time.NewTimer(timeout).C:
+			err = errors.Errorf(closeTimeoutErr, s.name, timeout)
+			jww.ERROR.Print(err.Error())
 		case s.quit <- struct{}{}:
 		}
-		atomic.StoreUint32(&s.running, 0)
+		atomic.StoreUint32(&s.running, stopped)
 	})
+
 	return err
 }

stoppable/single_test.go

@@ -8,96 +8,104 @@
 package stoppable
 
 import (
+	"fmt"
 	"testing"
 	"time"
 )
 
-// Tests happy path of NewSingle().
+// Tests that NewSingle returns a Single with the correct name and running.
 func TestNewSingle(t *testing.T) {
-	name := "test name"
+	name := "threadName"
 	single := NewSingle(name)
 
-	if single.name != name || single.running != 1 {
-		t.Errorf("NewSingle() returned Single with incorrect values."+
-			"\n\texpected:  name: %s  running: %d\n\treceived:  name: %s  running: %d",
-			name, 1, single.name, single.running)
+	if single.name != name {
+		t.Errorf("NewSingle returned Single with incorrect name."+
+			"\nexpected: %s\nreceived: %s", name, single.name)
+	}
+
+	if single.running != running {
+		t.Errorf("NewSingle returned Single with incorrect running."+
+			"\nexpected: %d\nreceived: %d", running, single.running)
 	}
 }
 
-// Tests happy path of Single.IsRunning().
+// Tests that Single.IsRunning returns the expected value when the Single is
+// marked as both running and not running.
 func TestSingle_IsRunning(t *testing.T) {
-	single := NewSingle("name")
+	single := NewSingle("threadName")
 
 	if !single.IsRunning() {
-		t.Errorf("IsRunning() returned false when it should be running.")
+		t.Errorf("IsRunning returned the wrong value when running."+
+			"\nexpected: %t\nreceived: %t", true, single.IsRunning())
 	}
 
-	single.running = 0
+	single.running = stopped
 	if single.IsRunning() {
-		t.Errorf("IsRunning() returned true when it should not be running.")
+		t.Errorf("IsRunning returned the wrong value when not running."+
+			"\nexpected: %t\nreceived: %t", false, single.IsRunning())
 	}
 }
 
-// Tests happy path of Single.Quit().
+// Tests that Single.Quit returns a channel that is triggered when the Single
+// quit channel is triggered.
 func TestSingle_Quit(t *testing.T) {
-	single := NewSingle("name")
+	single := NewSingle("threadName")
 
 	go func() {
-		time.Sleep(150 * time.Nanosecond)
-		single.quit <- struct{}{}
-	}()
-
-	timer := time.NewTimer(2 * time.Millisecond)
 		select {
-	case <-timer.C:
-		t.Errorf("Quit signal not received.")
-	case <-single.quit:
+		case <-time.NewTimer(5 * time.Millisecond).C:
+			t.Error("Timed out waiting for quit channel.")
+		case <-single.Quit():
 		}
+	}()
+
+	single.quit <- struct{}{}
 }
 
-// Tests happy path of Single.Name().
+// Unit test of Single.Name.
 func TestSingle_Name(t *testing.T) {
-	name := "test name"
+	name := "threadName"
 	single := NewSingle(name)
 
 	if name != single.Name() {
-		t.Errorf("Name() returned the incorrect string."+
-			"\n\texpected: %s\n\treceived: %s", name, single.Name())
+		t.Errorf("Name did not return the expected name."+
+			"\nexpected: %s\nreceived: %s", name, single.Name())
 	}
 }
 
 // Test happy path of Single.Close().
 func TestSingle_Close(t *testing.T) {
-	single := NewSingle("name")
+	single := NewSingle("threadName")
 
 	go func() {
-		time.Sleep(150 * time.Nanosecond)
 		select {
-		case <-single.quit:
+		case <-time.NewTimer(10 * time.Millisecond).C:
+			t.Error("Timed out waiting for quit channel.")
+		case <-single.Quit():
 		}
 	}()
 
 	err := single.Close(5 * time.Millisecond)
 	if err != nil {
-		t.Errorf("Close() returned an error: %v", err)
+		t.Errorf("Close returned an error: %v", err)
 	}
 }
 
-// Tests that Single.Close() returns an error when the timeout is reached.
+// Error path: tests that Single.Close returns an error when the timeout is
+// reached.
 func TestSingle_Close_Error(t *testing.T) {
-	single := NewSingle("name")
-	expectedErr := single.name + " failed to close"
+	single := NewSingle("threadName")
+	timeout := time.Millisecond
+	expectedErr := fmt.Sprintf(closeTimeoutErr, single.Name(), timeout)
 
 	go func() {
-		time.Sleep(3 * time.Millisecond)
-		select {
-		case <-single.quit:
-		}
+		time.Sleep(5 * time.Millisecond)
+		<-single.Quit()
 	}()
 
-	err := single.Close(2 * time.Millisecond)
-	if err == nil {
-		t.Errorf("Close() did not return the expected error."+
-			"\n\texpected: %v\n\treceived: %v", expectedErr, err)
+	err := single.Close(timeout)
+	if err == nil || err.Error() != expectedErr {
+		t.Errorf("Close did not return the expected error."+
+			"\nexpected: %s\nreceived: %v", expectedErr, err)
 	}
 }

stoppable/stoppable.go

@@ -9,7 +9,12 @@ package stoppable
 
 import "time"
 
-// Interface for stopping a goroutine.
+const (
+	stopped = 0
+	running = 1
+)
+
+// Stoppable interface for stopping a goroutine.
 type Stoppable interface {
 	Close(timeout time.Duration) error
 	IsRunning() bool