cli/hints: add tests

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/hints/hints.go

@@ -5,7 +5,9 @@ import (
 	"strconv"
 )
 
-// Enabled returns whether cli hints are enabled or not
+// Enabled returns whether cli hints are enabled or not. Hints are enabled by
+// default, but can be disabled through the "DOCKER_CLI_HINTS" environment
+// variable.
 func Enabled() bool {
 	if v := os.Getenv("DOCKER_CLI_HINTS"); v != "" {
 		enabled, err := strconv.ParseBool(v)

cli/hints/hints_test.go

@@ -0,0 +1,52 @@
+package hints
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestEnabled(t *testing.T) {
+	tests := []struct {
+		doc      string
+		env      string
+		expected bool
+	}{
+		{
+			doc:      "default",
+			expected: true,
+		},
+		{
+			doc:      "DOCKER_CLI_HINTS=1",
+			env:      "1",
+			expected: true,
+		},
+		{
+			doc:      "DOCKER_CLI_HINTS=true",
+			env:      "true",
+			expected: true,
+		},
+		{
+			doc:      "DOCKER_CLI_HINTS=0",
+			env:      "0",
+			expected: false,
+		},
+		{
+			doc:      "DOCKER_CLI_HINTS=false",
+			env:      "false",
+			expected: false,
+		},
+		{
+			doc:      "DOCKER_CLI_HINTS=not-a-bool",
+			env:      "not-a-bool",
+			expected: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.doc, func(t *testing.T) {
+			t.Setenv("DOCKER_CLI_HINTS", tc.env)
+			assert.Equal(t, Enabled(), tc.expected)
+		})
+	}
+}