Technical/Fix flaky tests (#188)

Author: bestwebua

helpers.go

@@ -3,6 +3,7 @@ package smtpmock
 import (
 	"fmt"
 	"regexp"
+	"time"
 )
 
 // Regex builder
@@ -20,8 +21,8 @@ func matchRegex(strContext, regexPattern string) bool {
 	return regex.MatchString(strContext)
 }
 
-// Returns string by regex pattern capture group index. For cases when regex not matched or
-// capture group not found returns empty string
+// Returns string by regex pattern capture group index.
+// For cases when regex not matched or capture group not found returns empty string
 func regexCaptureGroup(str string, regexPattern string, captureGroup int) (capturedString string) {
 	var regex *regexp.Regexp
 	defer func() { _ = recover() }()
@@ -47,3 +48,8 @@ func isIncluded(slice []string, target string) bool {
 func serverWithPortNumber(server string, portNumber int) string {
 	return fmt.Sprintf("%s:%d", server, portNumber)
 }
+
+// Sleeps for the given duration in milliseconds
+func sleepMilliseconds(duration int) {
+	time.Sleep(time.Duration(duration) * time.Millisecond)
+}

smtpmock_test.go

@@ -3,7 +3,6 @@ package smtpmock
 import (
 	"fmt"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -154,9 +153,12 @@ func TestNew(t *testing.T) {
 		assert.False(t, server.isStarted())
 
 		assert.NoError(t, server.Start())
+		sleepMilliseconds(100)
 		assert.True(t, server.isStarted())
 		_ = runSuccessfulSMTPSession(configuration.hostAddress, server.PortNumber(), true, 0)
+		sleepMilliseconds(100)
 		_ = server.Stop()
+		sleepMilliseconds(100)
 
 		assert.Equal(t, 2, len(server.Messages()))
 		assert.NotNil(t, server.quit)
@@ -221,11 +223,11 @@ func TestServerMessagesRaceCondition(t *testing.T) {
 		}()
 
 		// ensure that server.MessagesAndPurge() doesn't touch messages from active SMTP-session
-		time.Sleep(5 * time.Millisecond)
+		sleepMilliseconds(5)
 		assert.Empty(t, server.MessagesAndPurge())
 
 		// ensure that messages appears after SMTP-session
-		time.Sleep(100 * time.Millisecond)
+		sleepMilliseconds(100)
 		assert.Len(t, server.Messages(), 1)
 
 		if err := server.Stop(); err != nil {