Example of creating unit tests using the table driven approach

tdt-with-functions.go

func TestWithFunctions(t *testing.T) {
    type setupFunc func(t *testing.T, <other options>)
    type checkFunc func(t *testing.T, <other options>)

    testCases := map[string]struct{
        setupFn    setupFunc
        checkFn    checkFunc
        wantResult interface{}
        wantError  error
    }{
        "Name of the test": {
            setupFn: func(t *testing.T, <other options>) {
                // Perform all the setup for this case
            },
            checkFn: func(t *testing.T, actualResult, wantResult interface{}, actualError, wantError error, <other options>) {
                if !reflect.DeepEqual(wantResult, actualResult) {
                    t.Errorf("Expected to get %v as result but got %v", wantResult, actualResult)
                }

                if wantError == actualError {
                    t.Errorf("Expected to get %v as error but got %v", wantError, actualError)
                }

                // Perform the rest checks you need for this case...
            },
            wantResult: interface{},
            wantError: nil,
        },
        // Rest of test cases...
    }

    for name, tc := range testCases {
        t.Run(name, func(t *testing.T) {
            tc.setupFn(t, <rest of args>)

            actualResult, actualError := <the function to call>(...)

            tc.checkFn(t, actualResult, tc.wantResult, actualError, tc.wantError)
        })
    }
}