example_testup_test.go

package testup_test

import (
	"io/ioutil"
	"os"
	"path/filepath"
	"testing"

	"github.com/devnev/testup"
)

// testOsStat emulates what a Test function for os.Stat might look like when using testup.Suite.
func testOsStat(t *testing.T) {
	// The entire callback to testup.Suite is run three times: once as a prelude, and once for every
	// callback to test. Any setup and teardown that should be executed once for the entire suite
	// should be placed before the call to testup.Suite.
	testup.Suite(t, func(t *testing.T, test testup.Register) {
		test("of a directory", func() {
			// This setup and teardown code is re-executed in each of the three runs.
			dir, err := ioutil.TempDir(".", "test")
			if err != nil {
				t.Fatalf("unable to create test directory: %s", err)
			}
			// Teardown can be done using regular defer
			defer func() {
				err = os.RemoveAll(dir)
				if err != nil {
					t.Fatalf("unable to remove test directory: %s", err)
				}
			}()

			// In the first "prelude" run, none of the test callbacks below are executed.
			// Along with registering all the test cases, this allows testing the setup and teardown
			// in isolation.

			// In the second run, only this callback is executed
			test("dir is a directory", func() {
				fi, err := os.Stat(dir)
				if err != nil {
					t.Fatalf("unexpected error from stat: %s", err)
				}
				if !fi.IsDir() {
					t.Fatal("expected FileInfo.IsDir() to return true")
				}
			})
			// In the third run, only this callback is executed
			test("dir contains created file", func() {
				// We can safely mutate resource used in other test cases as each case is started
				// with a fresh setup
				err := ioutil.WriteFile(filepath.Join(dir, "testfile"), []byte("data"), 0644)
				if err != nil {
					t.Fatalf("unexpected error from writefile: %s", err)
				}
				items, err := ioutil.ReadDir(dir)
				if err != nil {
					t.Fatalf("unexpected error from readdir: %s", err)
				}
				if len(items) != 1 || items[0].Name() != "testfile" {
					t.Fatalf("expected results to contain only testfile, got %+v", items)
				}
			})
		})

		test("of a file", func() {
			// This setup and teardown code is executed twice, once without the sub-test and once
			// with the sub-test.
			file, err := ioutil.TempFile(".", "test")
			if err != nil {
				t.Fatalf("unable to create test directory: %s", err)
			}
			defer func() {
				err = os.RemoveAll(file.Name())
				if err != nil {
					t.Fatalf("unable to remove test directory: %s", err)
				}
			}()

			test("reports not a directory", func() {
				fi, err := os.Stat(file.Name())
				if err != nil {
					t.Fatalf("unexpected error from stat: %v", err)
				}
				if fi.IsDir() {
					t.Fatalf("expected FileInfo.IsDir() to return false")
				}
			})
		})
	})
}

func ExampleSuite() {
	// See testOsStat
}