github.com/u-root/u-root@v7.0.1-0.20200915234505-ad7babab0a8e+incompatible/cmds/core/elvish/util/throw_test.go (about)

     1  package util
     2  
     3  import (
     4  	"errors"
     5  	"testing"
     6  )
     7  
     8  func recoverPanic(f func()) (recovered interface{}) {
     9  	defer func() {
    10  		recovered = recover()
    11  	}()
    12  	f()
    13  	return nil
    14  }
    15  
    16  func TestThrowAndCatch(t *testing.T) {
    17  	tothrow := errors.New("an error to throw")
    18  	// Throw should cause a panic
    19  	f := func() {
    20  		Throw(tothrow)
    21  	}
    22  	if recoverPanic(f) == nil {
    23  		t.Errorf("Throw did not cause a panic")
    24  	}
    25  
    26  	// Catch should catch what was thrown
    27  	caught := func() (err error) {
    28  		defer Catch(&err)
    29  		Throw(tothrow)
    30  		return nil
    31  	}()
    32  	if caught != tothrow {
    33  		t.Errorf("thrown %v, but caught %v", tothrow, caught)
    34  	}
    35  
    36  	// Catch should not recover panics not caused by Throw
    37  	var err error
    38  	f = func() {
    39  		defer Catch(&err)
    40  		panic(errors.New("233"))
    41  	}
    42  	_ = recoverPanic(f)
    43  	if err != nil {
    44  		t.Errorf("Catch recovered panic not caused via Throw")
    45  	}
    46  
    47  	// Catch should do nothing when there is no panic
    48  	err = nil
    49  	f = func() {
    50  		defer Catch(&err)
    51  	}
    52  	f()
    53  	if err != nil {
    54  		t.Errorf("Catch recovered something when there is no panic")
    55  	}
    56  }
    57  
    58  // errToThrow is the error to throw in test cases.
    59  var errToThrow = errors.New("error to throw")
    60  
    61  func TestPCall(t *testing.T) {
    62  	// PCall catches throws
    63  	if PCall(func() { Throw(errToThrow) }) != errToThrow {
    64  		t.Errorf("PCall does not catch throws")
    65  	}
    66  	// PCall returns nil when nothing has been thrown
    67  	if PCall(func() {}) != nil {
    68  		t.Errorf("PCall returns non-nil when nothing has been thrown")
    69  	}
    70  	// PCall returns nil when nil has been thrown
    71  	if PCall(func() { Throw(nil) }) != nil {
    72  		t.Errorf("PCall returns non-nil when nil has been thrown")
    73  	}
    74  }
    75  
    76  func TestThrows(t *testing.T) {
    77  	if Throws(func() { Throw(errToThrow) }, errToThrow) != true {
    78  		t.Errorf("Throws returns false when function throws wanted error")
    79  	}
    80  	if Throws(func() { Throw(errToThrow) }, errors.New("")) != false {
    81  		t.Errorf("Throws returns true when function throws unwanted error")
    82  	}
    83  	if Throws(func() {}, errToThrow) != false {
    84  		t.Errorf("Throws returns true when function does not throw")
    85  	}
    86  }
    87  
    88  func TestThrowsAny(t *testing.T) {
    89  	if ThrowsAny(func() { Throw(errToThrow) }) != true {
    90  		t.Errorf("ThrowsAny returns false when function throws non-nil")
    91  	}
    92  	if ThrowsAny(func() {}) != false {
    93  		t.Errorf("ThrowsAny returns true when function does not throw")
    94  	}
    95  }
    96  
    97  func TestDoesnotThrow(t *testing.T) {
    98  	if DoesntThrow(func() { Throw(errToThrow) }) != false {
    99  		t.Errorf("DoesntThrow returns true when function throws")
   100  	}
   101  	if DoesntThrow(func() {}) != true {
   102  		t.Errorf("DoesntThrow returns false when function doesn't throw")
   103  	}
   104  }