Add a test case for flag requiring an argument (#70)

internal/flag/set.go

@@ -273,7 +273,6 @@ func (s *Set) parseLongFlag(long string, rest []string) (remaining []string, err
 		return rest[1:], nil
 	default:
 		// --flag (value was required)
-		// Do we ever hit this? Idk when a flag would be required
 		return nil, fmt.Errorf("flag --%s requires an argument", name)
 	}
 }

internal/flag/set_test.go

@@ -425,6 +425,33 @@ func TestParse(t *testing.T) {
 			args:    []string{"--count", "1"},
 			wantErr: false,
 		},
+		{
+			name: "valid long missing value",
+			newSet: func(t *testing.T) *flag.Set {
+				t.Helper()
+				set := flag.NewSet()
+				f, err := flag.New(new(int), "count", 'c', 0, "Count something")
+				test.Ok(t, err)
+
+				err = flag.AddToSet(set, f)
+				test.Ok(t, err)
+
+				return set
+			},
+			test: func(t *testing.T, set *flag.Set) {
+				t.Helper()
+				entry, exists := set.Get("count")
+				test.True(t, exists)
+
+				test.Equal(t, entry.Value.Type(), "int")
+				test.Equal(t, entry.Value.String(), "0")
+
+				test.EqualFunc(t, set.Args(), nil, slices.Equal)
+			},
+			args:    []string{"--count"}, // Count needs an argument
+			wantErr: true,
+			errMsg:  "flag --count requires an argument",
+		},
 		{
 			name: "valid long value with args",
 			newSet: func(t *testing.T) *flag.Set {