update tests

app_regression_test.go

@@ -6,7 +6,24 @@ import (
 
 // TestRegression tests a regression that was merged between versions 1.20.0 and 1.21.0
 // The included app.Run line worked in 1.20.0, and then was broken in 1.21.0.
+// Relevant PR: https://github.com/urfave/cli/pull/872
 func TestVersionOneTwoOneRegression(t *testing.T) {
+	testData := []struct {
+		testCase    string
+		appRunInput []string
+	}{
+		// assertion: empty input, when a required flag is present, errors
+		{
+			testCase:    "with_dash_dash",
+			appRunInput: []string{"cli", "command", "--flagone", "flagvalue", "--", "docker", "image", "ls", "--no-trunc"},
+		},
+		{
+			testCase:    "without_dash_dash",
+			appRunInput: []string{"cli", "command", "--flagone", "flagvalue", "docker", "image", "ls", "--no-trunc"},
+		},
+	}
+	for _, test := range testData {
+		t.Run(test.testCase, func(t *testing.T) {
 			// setup
 			app := NewApp()
 			app.Commands = []Command{{
@@ -20,10 +37,12 @@ func TestVersionOneTwoOneRegression(t *testing.T) {
 			}}
 
 			// logic under test
-	err := app.Run([]string{"cli", "command", "--flagone", "flagvalue", "docker", "image", "ls", "--no-trunc"})
+			err := app.Run(test.appRunInput)
 
 			// assertions
 			if err != nil {
 				t.Errorf("did not expected an error, but there was one: %s", err)
 			}
+		})
+	}
 }