github.com/haraldrudell/parl@v0.4.176/cancel-context_test.go (about)

     1  /*
     2  © 2022–present Harald Rudell <harald.rudell@gmail.com> (https://haraldrudell.github.io/haraldrudell/)
     3  ISC License
     4  */
     5  
     6  package parl
     7  
     8  import (
     9  	"context"
    10  	"errors"
    11  	"strings"
    12  	"sync/atomic"
    13  	"testing"
    14  	"time"
    15  
    16  	"github.com/haraldrudell/parl/perrors/errorglue"
    17  )
    18  
    19  // tests:
    20  // NewCancelContext
    21  // NewCancelContextFunc
    22  // InvokeCancel
    23  // HasCancel
    24  func TestInvokeCancel(t *testing.T) {
    25  	// nil parent”
    26  	var messageNilParent = "nil parent"
    27  	// “ctx cannot be nil”
    28  	var messageCtxNil = "ctx cannot be nil"
    29  
    30  	var ctx context.Context
    31  	var err error
    32  	var isPanic bool
    33  
    34  	// regular context
    35  	ctx = context.Background()
    36  	// HasCancel should be false
    37  	if HasCancel(ctx) {
    38  		t.Error("context HasCancel")
    39  	}
    40  	// InvokeCancel should panic
    41  	isPanic, err = invokeInvokeCancel(ctx)
    42  	if !isPanic || err == nil {
    43  		t.Error("InvokeCancel no panic")
    44  	}
    45  	if !errors.Is(err, ErrNotCancelContext) {
    46  		t.Errorf("err not ErrNotCancelContext %s “%+[1]v”",
    47  			errorglue.DumpChain(err),
    48  			err,
    49  		)
    50  	}
    51  
    52  	// cancelContext
    53  	ctx = NewCancelContext(ctx)
    54  	// should not be canceled
    55  	if ctx.Err() != nil {
    56  		t.Error("context was canceled")
    57  	}
    58  	// HasCancel should be true
    59  	if !HasCancel(ctx) {
    60  		t.Error("context not HasCancel")
    61  	}
    62  
    63  	// InvokeCancel should cancel the context
    64  	InvokeCancel(ctx)
    65  	if ctx.Err() == nil {
    66  		t.Error("InvokeCancel did not cancel")
    67  	}
    68  
    69  	ctx = nil
    70  	_, isPanic, err = invokeNewCancelContext(ctx)
    71  	if !isPanic {
    72  		t.Error("NewCancelContext nil no panic")
    73  	}
    74  	if err == nil || !strings.Contains(err.Error(), messageNilParent) {
    75  		t.Errorf("InvokeCancel bad error: %v exp %q", err, messageNilParent)
    76  	}
    77  
    78  	isPanic, err = invokeInvokeCancel(ctx)
    79  	if !isPanic {
    80  		t.Error("InvokeCancel nil no panic")
    81  	}
    82  	if err == nil || !strings.Contains(err.Error(), messageCtxNil) {
    83  		t.Errorf("InvokeCancel bad error: '%v' exp %q", err, messageCtxNil)
    84  	}
    85  }
    86  
    87  func TestCancelOnError(t *testing.T) {
    88  	var err error
    89  
    90  	// nil,nil should not panic
    91  	CancelOnError(nil, nil)
    92  
    93  	CancelOnError(&err, nil)
    94  	ctx := NewCancelContext(context.Background())
    95  	err = errors.New("x")
    96  	CancelOnError(&err, ctx)
    97  	if ctx.Err() == nil {
    98  		t.Log("CancelOnError failed")
    99  	}
   100  }
   101  
   102  func TestAfterFunc(t *testing.T) {
   103  	var duration = time.Second
   104  
   105  	var ctx = NewCancelContext(context.Background())
   106  	var counter = newInvokeDetector()
   107  	context.AfterFunc(ctx, counter.Func)
   108  
   109  	// invokeCancel should start counter.Func in separate goroutine
   110  	InvokeCancel(ctx)
   111  	counter.waitForCh(duration)
   112  	if c := counter.u32.Load(); c != 1 {
   113  		t.Errorf("Bad number of invocations: %d exp 1", c)
   114  	}
   115  }
   116  
   117  // invokeInvokeCancel calls InvokeCancel recovering panic
   118  func invokeInvokeCancel(ctx context.Context) (isPanic bool, err error) {
   119  	defer PanicToErr(&err, &isPanic)
   120  
   121  	InvokeCancel(ctx)
   122  	return
   123  }
   124  
   125  // invokeNewCancelContext invokes NewCancelContext recovering panic
   126  func invokeNewCancelContext(ctx context.Context) (ctx2 context.Context, isPanic bool, err error) {
   127  	defer PanicToErr(&err, &isPanic)
   128  
   129  	ctx2 = NewCancelContext(ctx)
   130  
   131  	return
   132  }
   133  
   134  // invokeDetector counts invocations
   135  type invokeDetector struct {
   136  	u32 atomic.Uint32
   137  	ch  chan struct{}
   138  }
   139  
   140  // newInvokeDetector retruns an object counting invocations
   141  func newInvokeDetector() (i *invokeDetector) { return &invokeDetector{ch: make(chan struct{})} }
   142  
   143  func (i *invokeDetector) Func() {
   144  	if i.u32.Add(1) == 1 {
   145  		close(i.ch)
   146  	}
   147  }
   148  
   149  // waitForCh wait up to d for first Func invocation
   150  func (i *invokeDetector) waitForCh(d time.Duration) {
   151  	var timer = time.NewTimer(d)
   152  	defer timer.Stop()
   153  
   154  	select {
   155  	case <-i.ch:
   156  	case <-timer.C:
   157  	}
   158  }
   159  
   160  func TestChildCancel(t *testing.T) {
   161  	var v any
   162  	var a func()
   163  	var ok bool
   164  	a, ok = v.(func())
   165  	_ = a
   166  	_ = ok
   167  
   168  	// create ctx0…3
   169  	var ctx0 = context.Background()
   170  	var ctx1 = AddNotifier(ctx0, func(stack Stack) {
   171  		t.Log(stack)
   172  	})
   173  	var ctx2 = NewCancelContext(ctx1)
   174  	var ctx3 = NewCancelContext(ctx2)
   175  
   176  	// cancel ctx3 should cancel only ctx3
   177  	invokeCancel(ctx3)
   178  	if ctx3.Err() == nil {
   179  		t.Error("ctx3 not canceled")
   180  	}
   181  	if ctx2.Err() != nil {
   182  		t.Error("ctx2 canceled")
   183  	}
   184  	if ctx1.Err() != nil {
   185  		t.Error("ctx1 canceled")
   186  	}
   187  	if ctx0.Err() != nil {
   188  		t.Error("ctx0 canceled")
   189  	}
   190  }