fix data race

main.go

@@ -163,7 +163,7 @@ func (c *Client) pester(p params) (*http.Response, error) {
 	}
 
 	if c.hc == nil {
-		c.hc = http.DefaultClient
+		c.hc = &http.Client{}
 		c.hc.Transport = c.Transport
 		c.hc.CheckRedirect = c.CheckRedirect
 		c.hc.Jar = c.Jar
@@ -298,6 +298,8 @@ func (c *Client) pester(p params) (*http.Response, error) {
 
 // LogString provides a string representation of the errors the client has seen
 func (c *Client) LogString() string {
+	c.Lock()
+	defer c.Unlock()
 	var res string
 	for _, e := range c.ErrLog {
 		res += fmt.Sprintf("%d %s [%s] %s request-%d retry-%d error: %s\n",
@@ -306,6 +308,13 @@ func (c *Client) LogString() string {
 	return res
 }
 
+// LogErrCount is a helper method used primarily for test validation
+func (c *Client) LogErrCount() int {
+	c.Lock()
+	defer c.Unlock()
+	return len(c.ErrLog)
+}
+
 // EmbedHTTPClient allows you to extend an existing Pester client with an
 // underlying http.Client, such as https://godoc.org/golang.org/x/oauth2/google#DefaultClient
 func (c *Client) EmbedHTTPClient(hc *http.Client) {

main_test.go

@@ -19,7 +19,7 @@ func TestConcurrentRequests(t *testing.T) {
 	t.Parallel()
 
 	c := pester.New()
-	c.Concurrency = 4
+	c.Concurrency = 3
 	c.KeepLog = true
 
 	nonExistantURL := "http://localhost:9000/foo"
@@ -32,16 +32,16 @@ func TestConcurrentRequests(t *testing.T) {
 	// in the event of an error, let's see what the logs were
 	t.Log("\n", c.LogString())
 
-	if got, want := len(c.ErrLog), c.Concurrency*c.MaxRetries; got != want {
+	if got, want := c.LogErrCount(), c.Concurrency*c.MaxRetries; got != want {
 		t.Errorf("got %d attempts, want %d", got, want)
 	}
 }
 
-func TestConcurrent4Retry0(t *testing.T) {
+func TestConcurrent2Retry0(t *testing.T) {
 	t.Parallel()
 
 	c := pester.New()
-	c.Concurrency = 4
+	c.Concurrency = 2
 	c.MaxRetries = 0
 	c.KeepLog = true
 
@@ -55,7 +55,7 @@ func TestConcurrent4Retry0(t *testing.T) {
 	// in the event of an error, let's see what the logs were
 	t.Log("\n", c.LogString())
 
-	if got, want := len(c.ErrLog), c.Concurrency; got != want {
+	if got, want := c.LogErrCount(), c.Concurrency; got != want {
 		t.Errorf("got %d attempts, want %d", got, want)
 	}
 }
@@ -80,7 +80,7 @@ func TestDefaultBackoff(t *testing.T) {
 		t.Error("got %d, want %d for concurrency", got, want)
 	}
 
-	if got, want := len(c.ErrLog), c.MaxRetries; got != want {
+	if got, want := c.LogErrCount(), c.MaxRetries; got != want {
 		t.Fatalf("got %d errors, want %d", got, want)
 	}
 
@@ -151,7 +151,7 @@ func TestExponentialBackoff(t *testing.T) {
 	// in the event of an error, let's see what the logs were
 	t.Log("\n", c.LogString())
 
-	if got, want := len(c.ErrLog), c.MaxRetries; got != want {
+	if got, want := c.LogErrCount(), c.MaxRetries; got != want {
 		t.Fatalf("got %d errors, want %d", got, want)
 	}