add e2e tmpl test

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

test/e2e/template/helmfile/tmpl_test.go

@@ -0,0 +1,92 @@
+package helmfile
+
+import (
+	"bytes"
+	"os"
+	"testing"
+	"text/template"
+
+	"github.com/roboll/helmfile/pkg/tmpl"
+	"github.com/stretchr/testify/require"
+)
+
+type tmplTestCase struct {
+	//  envs are set in the test environment
+	envs map[string]string
+	// name of the test
+	name string
+	// tmplString is the template string to be parsed
+	tmplString string
+	// data is the data to be passed to the template
+	data interface{}
+	// wantErr is true if the template should fail to parse
+	wantErr bool
+	// output is the expected output of the template
+	output string
+}
+
+// setEnvs sets the environment variables for the test case
+func (t *tmplTestCase) setEnvs() {
+	for k, v := range t.envs {
+		os.Setenv(k, v)
+	}
+}
+
+// unSetEnvs unsets the environment variables for the test case
+func (t *tmplTestCase) unSetEnvs() {
+	for k := range t.envs {
+		os.Unsetenv(k)
+	}
+}
+
+// tmplTestCases are the test cases for the template tests
+var tmplTestCases = []tmplTestCase{
+	{
+		envs: map[string]string{
+			"TEST_VAR": "test",
+		},
+		name:       "requiredEnvWithEnvs",
+		tmplString: `{{ requiredEnv "TEST_VAR" }}`,
+		output:     "test",
+	},
+	{
+		name:       "requiredEnv",
+		tmplString: `{{ requiredEnv "TEST_VAR" }}`,
+		wantErr:    true,
+	},
+	{
+		name:       "requiredWithEmptyString",
+		tmplString: `{{ "" | required "required" }}`,
+		wantErr:    true,
+	},
+	{
+		name:       "required",
+		tmplString: `{{ "test" | required "required" }}`,
+		output:     "test",
+	},
+}
+
+// TestTmplStrings tests the template string
+func TestTmplStrings(t *testing.T) {
+	c := &tmpl.Context{}
+	tmpl := template.New("stringTemplateTest").Funcs(c.CreateFuncMap())
+
+	for _, tc := range tmplTestCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.setEnvs()
+			defer tc.unSetEnvs()
+			tmpl, err := tmpl.Parse(tc.tmplString)
+			require.Nilf(t, err, "error parsing template: %v", err)
+
+			var tplResult bytes.Buffer
+			err = tmpl.Execute(&tplResult, tc.data)
+			if tc.wantErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+			require.Equal(t, tc.output, tplResult.String())
+		})
+	}
+
+}