add more tests for Desired func (#1082)

Signed-off-by: yxxhero <aiopsclub@163.com>

pkg/state/release_test.go

@@ -43,3 +43,42 @@ func TestExecuteTemplateExpressions(t *testing.T) {
 	require.NoErrorf(t, err, "failed to execute template expressions: %v", err)
 	require.Equalf(t, result.ValuesTemplate[0].(map[string]any)["fullnameOverride"], "foo", "failed to execute template expressions")
 }
+
+func TestDesired(t *testing.T) {
+	cases := []struct {
+		name     string
+		expected bool
+		release  ReleaseSpec
+	}{
+		{
+			name:     "desired is true",
+			expected: true,
+			release: ReleaseSpec{
+				Installed: &[]bool{true}[0],
+			},
+		},
+		{
+			name:     "desired is false",
+			expected: false,
+			release: ReleaseSpec{
+				Installed: &[]bool{false}[0],
+			},
+		},
+		{
+			name:     "desired is nil",
+			expected: true,
+			release:  ReleaseSpec{},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual := tc.release.Desired()
+			require.Equal(t, tc.expected, actual)
+
+			// test compatibility with older versions of helmfile
+			// r.Installed != nil && !*r.Installed compare to !r.Desired()
+			require.Equal(t, tc.release.Installed != nil && !*tc.release.Installed, !actual)
+		})
+	}
+}