diff --git a/client/httpuils_test.go b/client/httpuils_test.go
index 580a7acf8..dfb660120 100644
--- a/client/httpuils_test.go
+++ b/client/httpuils_test.go
@@ -23,31 +23,41 @@ import (
 
 func TestParseHost(t *testing.T) {
 	tests := []struct {
-		name   string
-		host   string
-		expect error
+		name     string
+		host     string
+		expected error
 	}{
 		{
-			name:   "http host",
-			host:   "http://github.com",
-			expect: nil,
+			name:     "tcp host",
+			host:     "tcp://github.com",
+			expected: nil,
 		},
 		{
-			name:   "https host",
-			host:   "https://github.com",
-			expect: nil,
+			name:     "unix host",
+			host:     "unix://github.com",
+			expected: nil,
 		},
 		{
-			name:   "not support url scheme",
-			host:   "wss://github.com",
-			expect: errors.New("not support url scheme wss"),
+			name:     "http host",
+			host:     "http://github.com",
+			expected: nil,
+		},
+		{
+			name:     "https host",
+			host:     "https://github.com",
+			expected: nil,
+		},
+		{
+			name:     "not support url scheme",
+			host:     "wss://github.com",
+			expected: errors.New("not support url scheme wss"),
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			_, _, _, err := ParseHost(tt.host)
-			if (nil == err) != (nil == tt.expect) {
-				t.Errorf("expect: %v, got: %v\n", tt.expect, err)
+			if (nil == err) != (nil == tt.expected) {
+				t.Errorf("expected: %v, got: %v\n", tt.expected, err)
 			}
 		})
 	}
diff --git a/dfget/core/api/download_api_test.go b/dfget/core/api/download_api_test.go
index 5201e3629..640ac6b8e 100644
--- a/dfget/core/api/download_api_test.go
+++ b/dfget/core/api/download_api_test.go
@@ -36,6 +36,7 @@ func (s *DownloadAPITestSuite) TestGetRealRange(c *check.C) {
 		rangeValue string
 		expected   string
 	}{
+		{"", "0-1", ""},
 		{"0-1", "", "0-1"},
 		{"0-1", "1-100", "1-2"},
 		{"0-100", "1-100", "1-100"},
diff --git a/pkg/atomiccount/atomiccount_test.go b/pkg/atomiccount/atomiccount_test.go
index 5f9a92ee1..9fcf3642a 100644
--- a/pkg/atomiccount/atomiccount_test.go
+++ b/pkg/atomiccount/atomiccount_test.go
@@ -39,6 +39,9 @@ func (suite *AtomicCountUtilSuite) TestAdd(c *check.C) {
 
 	result := acount.Get()
 	c.Check(result, check.Equals, (int32)(12))
+
+	var nilAcount *AtomicInt
+	c.Check(nilAcount.Add(5), check.Equals, (int32)(0))
 }
 
 func (suite *AtomicCountUtilSuite) TestSet(c *check.C) {
@@ -49,4 +52,7 @@ func (suite *AtomicCountUtilSuite) TestSet(c *check.C) {
 	_ = acount.Set(1)
 	result := acount.Get()
 	c.Check(result, check.Equals, (int32)(1))
+
+	var nilAcount *AtomicInt
+	c.Check(nilAcount.Get(), check.Equals, (int32)(0))
 }