Golang-涵盖所有用例的文本/模板单元测试

Question

I've the following example (similar of what we have in prod) "text/template" code which works OK, now I want to create a unit test for it that checks the function and also the text/template to see that I cover 100% of the code...

The problem here is how to do the text/template unit test which covers all the cases. I'm currently new to text/template and I want to make sure it's working as expected.

Please visit: https://play.golang.org/p/203Al36Zigk

This is the template:

const tmpl = `#!/bin/bash
{{- range .File.Dependency}}
echo {{.EchoText}}
{{- range .Install}}
submitting {{.name}}
{{- end}}
{{.TypeCommand}}
{{end}}

{{- range $k, $v := .API}}
echo {{$k}}
submitting {{$v}}
{{end}}
`

Answer 1

You should setup a template_test file dedicated to testing the output of your template file.

For that, looking at the sources of the golang text/template package is always a good idea.

As an example (to be adapted to your case), you have src/text/template/example_test.go which uses a classic table-driven test approach:

package template_test

import (
    "log"
    "os"
    "strings"
    "text/template"
)

func ExampleTemplate() {
    // Define a template.
    const letter = `
Dear {{.Name}},
{{if .Attended}}
It was a pleasure to see you at the wedding.
{{- else}}
It is a shame you couldn't make it to the wedding.
{{- end}}
{{with .Gift -}}
Thank you for the lovely {{.}}.
{{end}}
Best wishes,
Josie
`

    // Prepare some data to insert into the template.
    type Recipient struct {
        Name, Gift string
        Attended   bool
    }
    var recipients = []Recipient{
        {"Aunt Mildred", "bone china tea set", true},
        {"Uncle John", "moleskin pants", false},
        {"Cousin Rodney", "", false},
    }

    // Create a new template and parse the letter into it.
    t := template.Must(template.New("letter").Parse(letter))

    // Execute the template for each recipient.
    for _, r := range recipients {
        err := t.Execute(os.Stdout, r)
        if err != nil {
            log.Println("executing template:", err)
        }
    }

    // Output:
    // Dear Aunt Mildred,
    //
    // It was a pleasure to see you at the wedding.
    // Thank you for the lovely bone china tea set.
    //
    // Best wishes,
    // Josie
    //
    // Dear Uncle John,
    //
    // It is a shame you couldn't make it to the wedding.
    // Thank you for the lovely moleskin pants.
    //
    // Best wishes,
    // Josie
    //
    // Dear Cousin Rodney,
    //
    // It is a shame you couldn't make it to the wedding.
    //
    // Best wishes,
    // Josie
}

For the assertion part, look in src/text/template/multi_test.go which defines multiParseTest as a structure with a template, *and an expected result, which allows to do assertions like:

result := tmpl.Root.String()
if result != test.results[i] {
    t.Errorf("%s=(%q): got
\t%v
expected
\t%v", test.name, test.input, result, test.results[i])
}