setup and teardown for each test using std testing package

Question

I am using go "testing" package. Running my tests like below.

func TestMain(m *testing.M) {     ...    // Setup    os.Exit(m.Run())    // Teardown } 

This will run a setup before any test is run, and a teardown after all tests are complete. And I do need this, as the setup sets the DB up. But also, I need, and yet to find out a way to run a per-test setup/teardown. For the unit tests I am running, I would like to clear the DB before every test, so that there are no issues with the content of the DB causing unexpected behavior.

Answer 1

Update for Go 1.14 (Q1 2020)

The testing package now supports cleanup functions, called after a test or benchmark has finished, by calling T.Cleanup or B.Cleanup respectively. Example,

func TestFunction(t *testing.T) {     // setup code     // sub-tests     t.Run()      t.Run()      ...     // cleanup     t.Cleanup(func(){         //tear-down code     }) } 

Here, t.Cleanup runs after the test and all its sub-tests are complete.

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Original answer (Feb. 2017)
As shown in the article "Go unit test setup and teardown" from Kare Nuorteva, you could use a setup function which returns... a teardown function to you defer.

See this gist:

func setupSubTest(t *testing.T) func(t *testing.T) {     t.Log("setup sub test")     return func(t *testing.T) {         t.Log("teardown sub test")     } } 

The setup function is in charge of defining and returning the teardown one.

For each test, for instance in a table-driven test scenario:

for _, tc := range cases {     t.Run(tc.name, func(t *testing.T) {         teardownSubTest := setupSubTest(t)         defer teardownSubTest(t)          result := Sum(tc.a, tc.b)         if result != tc.expected {             t.Fatalf("expected sum %v, but got %v", tc.expected, result)         }     }) } 

Answer 2

If table driven test pattern works for you, you should stick with it. If you need something more generic and flexible feel free to give https://github.com/houqp/gtest a try.

Here is a quick example:

import (   "strings"   "testing"   "github.com/houqp/gtest" )  type SampleTests struct{}  // Setup and Teardown are invoked per test group run func (s *SampleTests) Setup(t *testing.T)      {} func (s *SampleTests) Teardown(t *testing.T)   {} // BeforeEach and AfterEach are invoked per test run func (s *SampleTests) BeforeEach(t *testing.T) {} func (s *SampleTests) AfterEach(t *testing.T)  {}  func (s *SampleTests) SubTestCompare(t *testing.T) {   if 1 != 1 {     t.FailNow()   } }  func (s *SampleTests) SubTestCheckPrefix(t *testing.T) {   if !strings.HasPrefix("abc", "ab") {     t.FailNow()   } }  func TestSampleTests(t *testing.T) {   gtest.RunSubTests(t, &SampleTests{}) }