update: add case for tests WSL env

Author: inhere

detect_env.go

@@ -146,6 +146,8 @@ var wslContents string
 // https://github.com/Microsoft/WSL/issues/423#issuecomment-221627364
 func detectWSL() bool {
 	if !detectedWSL {
+		detectedWSL = true
+
 		b := make([]byte, 1024)
 		// `cat /proc/version`
 		// on mac:
@@ -164,10 +166,10 @@ func detectWSL() bool {
 			}
 
 			wslContents = string(b)
+			return strings.Contains(wslContents, "Microsoft")
 		}
-		detectedWSL = true
 	}
-	return strings.Contains(wslContents, "Microsoft")
+	return false
 }
 
 // refer

utils_test.go

@@ -107,6 +107,13 @@ func TestIsDetectColorLevel_unix(t *testing.T) {
 		is.True(IsSupportColor())
 	})
 
+	mockOsEnvByText("WSL_DISTRO_NAME=Debian", func() {
+		is.Equal(LevelNo, DetectColorLevel())
+		is.False(IsSupportTrueColor())
+		is.False(IsSupport256Color())
+		is.False(IsSupportColor())
+	})
+
 	// TERM_PROGRAM=Terminus
 	mockOsEnvByText(`
 TERMINUS_PLUGINS=