diff --git a/distribution/pull_v2_test.go b/distribution/pull_v2_test.go
index a4824dff08..76aeac2e40 100644
--- a/distribution/pull_v2_test.go
+++ b/distribution/pull_v2_test.go
@@ -3,7 +3,6 @@ package distribution // import "github.com/docker/docker/distribution"
 import (
 	"context"
 	"encoding/json"
-	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -210,7 +209,7 @@ func TestFormatPlatform(t *testing.T) {
 		}
 		matches, _ := regexp.MatchString("windows.* [0-9]", result)
 		if !matches {
-			t.Fatal(fmt.Sprintf("expected formatPlatform to show windows platform with a version, but got '%s'", result))
+			t.Fatalf("expected formatPlatform to show windows platform with a version, but got '%s'", result)
 		}
 	}
 }
diff --git a/integration-cli/docker_cli_build_test.go b/integration-cli/docker_cli_build_test.go
index 7f18a1d451..85c096bd77 100644
--- a/integration-cli/docker_cli_build_test.go
+++ b/integration-cli/docker_cli_build_test.go
@@ -5946,10 +5946,6 @@ func (s *DockerCLIBuildSuite) TestBuildMultiStageResetScratch(c *testing.T) {
 }
 
 func (s *DockerCLIBuildSuite) TestBuildIntermediateTarget(c *testing.T) {
-	//todo: need to be removed after 18.06 release
-	if strings.Contains(testEnv.DaemonInfo.ServerVersion, "18.05.0") {
-		c.Skip(fmt.Sprintf("Bug fixed in 18.06 or higher.Skipping it for %s", testEnv.DaemonInfo.ServerVersion))
-	}
 	dockerfile := `
 		FROM busybox AS build-env
 		CMD ["/dev"]
diff --git a/integration-cli/docker_cli_daemon_test.go b/integration-cli/docker_cli_daemon_test.go
index a51f2d0419..bdfbcd039f 100644
--- a/integration-cli/docker_cli_daemon_test.go
+++ b/integration-cli/docker_cli_daemon_test.go
@@ -237,7 +237,7 @@ func (s *DockerDaemonSuite) TestDaemonRestartWithIncreasedBasesize(c *testing.T)
 	var newBasesizeBytes int64 = 53687091200 // 50GB in bytes
 
 	if newBasesizeBytes < oldBasesizeBytes {
-		c.Skip(fmt.Sprintf("New base device size (%v) must be greater than (%s)", units.HumanSize(float64(newBasesizeBytes)), units.HumanSize(float64(oldBasesizeBytes))))
+		c.Skipf("New base device size (%v) must be greater than (%s)", units.HumanSize(float64(newBasesizeBytes)), units.HumanSize(float64(oldBasesizeBytes)))
 	}
 
 	err := s.d.RestartWithError("--storage-opt", fmt.Sprintf("dm.basesize=%d", newBasesizeBytes))
diff --git a/libnetwork/firewall_linux.go b/libnetwork/firewall_linux.go
index 590e61f2af..a990ec8e91 100644
--- a/libnetwork/firewall_linux.go
+++ b/libnetwork/firewall_linux.go
@@ -7,9 +7,7 @@ import (
 
 const userChain = "DOCKER-USER"
 
-var (
-	ctrl *controller = nil
-)
+var ctrl *controller
 
 func setupArrangeUserFilterRule(c *controller) {
 	ctrl = c