helperfuncs_test.go

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package testing
     6  
     7  import "sync"
     8  
     9  // The line numbering of this file is important for TestTBHelper.
    10  
    11  func notHelper(t *T, msg string) {
    12  	t.Error(msg)
    13  }
    14  
    15  func helper(t *T, msg string) {
    16  	t.Helper()
    17  	t.Error(msg)
    18  }
    19  
    20  func notHelperCallingHelper(t *T, msg string) {
    21  	helper(t, msg)
    22  }
    23  
    24  func helperCallingHelper(t *T, msg string) {
    25  	t.Helper()
    26  	helper(t, msg)
    27  }
    28  
    29  func genericHelper[G any](t *T, msg string) {
    30  	t.Helper()
    31  	t.Error(msg)
    32  }
    33  
    34  var genericIntHelper = genericHelper[int]
    35  
    36  func testHelper(t *T) {
    37  	// Check combinations of directly and indirectly
    38  	// calling helper functions.
    39  	notHelper(t, "0")
    40  	helper(t, "1")
    41  	notHelperCallingHelper(t, "2")
    42  	helperCallingHelper(t, "3")
    43  
    44  	// Check a function literal closing over t that uses Helper.
    45  	fn := func(msg string) {
    46  		t.Helper()
    47  		t.Error(msg)
    48  	}
    49  	fn("4")
    50  
    51  	t.Run("sub", func(t *T) {
    52  		helper(t, "5")
    53  		notHelperCallingHelper(t, "6")
    54  		// Check that calling Helper from inside a subtest entry function
    55  		// works as if it were in an ordinary function call.
    56  		t.Helper()
    57  		t.Error("7")
    58  	})
    59  
    60  	// Check that calling Helper from inside a top-level test function
    61  	// has no effect.
    62  	t.Helper()
    63  	t.Error("8")
    64  
    65  	// Check that right caller is reported for func passed to Cleanup when
    66  	// multiple cleanup functions have been registered.
    67  	t.Cleanup(func() {
    68  		t.Helper()
    69  		t.Error("10")
    70  	})
    71  	t.Cleanup(func() {
    72  		t.Helper()
    73  		t.Error("9")
    74  	})
    75  
    76  	// Check that helper-ness propagates up through subtests
    77  	// to helpers above. See https://golang.org/issue/44887.
    78  	helperSubCallingHelper(t, "11")
    79  
    80  	// Check that helper-ness propagates up through panic/recover.
    81  	// See https://golang.org/issue/31154.
    82  	recoverHelper(t, "12")
    83  
    84  	genericHelper[float64](t, "GenericFloat64")
    85  	genericIntHelper(t, "GenericInt")
    86  }
    87  
    88  func parallelTestHelper(t *T) {
    89  	var wg sync.WaitGroup
    90  	for i := 0; i < 5; i++ {
    91  		wg.Add(1)
    92  		go func() {
    93  			notHelperCallingHelper(t, "parallel")
    94  			wg.Done()
    95  		}()
    96  	}
    97  	wg.Wait()
    98  }
    99  
   100  func helperSubCallingHelper(t *T, msg string) {
   101  	t.Helper()
   102  	t.Run("sub2", func(t *T) {
   103  		t.Helper()
   104  		t.Fatal(msg)
   105  	})
   106  }
   107  
   108  func recoverHelper(t *T, msg string) {
   109  	t.Helper()
   110  	defer func() {
   111  		t.Helper()
   112  		if err := recover(); err != nil {
   113  			t.Errorf("recover %s", err)
   114  		}
   115  	}()
   116  	doPanic(t, msg)
   117  }
   118  
   119  func doPanic(t *T, msg string) {
   120  	t.Helper()
   121  	panic(msg)
   122  }
   123
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