Unit test zero join attempts

cluster/join.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/tls"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"log"
@@ -16,6 +17,11 @@ import (
 	httpd "github.com/rqlite/rqlite/http"
 )
 
+var (
+	// ErrJoinFailed is returned when a node fails to join a cluster
+	ErrJoinFailed = errors.New("failed to join cluster")
+)
+
 // Join attempts to join the cluster at one of the addresses given in joinAddr.
 // It walks through joinAddr in order, and sets the node ID and Raft address of
 // the joining node as id addr respectively. It returns the endpoint successfully
@@ -41,7 +47,7 @@ func Join(joinAddr []string, id, addr string, voter bool, meta map[string]string
 		time.Sleep(attemptInterval)
 	}
 	logger.Printf("failed to join cluster at %s, after %d attempts", joinAddr, numAttempts)
-	return "", err
+	return "", ErrJoinFailed
 }
 
 func join(joinAddr, id, addr string, voter bool, meta map[string]string, tlsConfig *tls.Config, logger *log.Logger) (string, error) {

cluster/join_test.go

@@ -55,6 +55,17 @@ func Test_SingleJoinOK(t *testing.T) {
 	}
 }
 
+func Test_SingleJoinZeroAttempts(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Fatalf("handler should not have been called")
+	}))
+
+	_, err := Join([]string{ts.URL}, "id0", "127.0.0.1:9090", false, nil, 0, attemptInterval, nil)
+	if err != ErrJoinFailed {
+		t.Fatalf("Incorrect error returned when zero attempts specified")
+	}
+}
+
 func Test_SingleJoinMetaOK(t *testing.T) {
 	var body map[string]interface{}