Add test coverage for sinks; prevent panic on nil channels

This commit is contained in:
Dane Everitt 2022-01-23 10:41:12 -05:00
parent a4904365c9
commit c52db4eec0
2 changed files with 203 additions and 5 deletions

View File

@ -52,10 +52,12 @@ func (p *sinkPool) Off(c chan []byte) {
copy(sinks[i:], sinks[i+1:])
sinks[len(sinks)-1] = nil
sinks = sinks[:len(sinks)-1]
// Update our tracked sinks, and close the matched channel.
p.sinks = sinks
close(c)
// Avoid a panic if the sink channel is nil at this point.
if c != nil {
close(c)
}
return
}
@ -68,7 +70,9 @@ func (p *sinkPool) Destroy() {
defer p.mu.Unlock()
for _, c := range p.sinks {
close(c)
if c != nil {
close(c)
}
}
p.sinks = nil
@ -77,10 +81,15 @@ func (p *sinkPool) Destroy() {
// Push sends a given message to each of the channels registered in the pool.
func (p *sinkPool) Push(data []byte) {
p.mu.RLock()
// Attempt to send the data over to the channels. If the channel buffer is full,
// or otherwise blocked for some reason (such as being a nil channel), just discard
// the event data and move on to the next channel in the slice. If you don't
// implement the "default" on the select you'll block execution until the channel
// becomes unblocked, which is not what we want to do here.
for _, c := range p.sinks {
select {
// Send the event data over to the channels.
case c <- data:
default:
}
}
p.mu.RUnlock()

189
server/sink_test.go Normal file
View File

@ -0,0 +1,189 @@
package server
import (
"reflect"
"sync"
"testing"
. "github.com/franela/goblin"
)
func MutexLocked(m *sync.RWMutex) bool {
v := reflect.ValueOf(m).Elem()
state := v.FieldByName("w").FieldByName("state")
return state.Int()&1 == 1 || v.FieldByName("readerCount").Int() > 0
}
func Test(t *testing.T) {
g := Goblin(t)
g.Describe("SinkPool#On", func() {
g.It("pushes additional channels to a sink", func() {
pool := &sinkPool{}
g.Assert(pool.sinks).IsZero()
c1 := make(chan []byte, 1)
pool.On(c1)
g.Assert(len(pool.sinks)).Equal(1)
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
})
g.Describe("SinkPool#Off", func() {
var pool *sinkPool
g.BeforeEach(func() {
pool = &sinkPool{}
})
g.It("works when no sinks are registered", func() {
ch := make(chan []byte, 1)
g.Assert(pool.sinks).IsZero()
pool.Off(ch)
g.Assert(pool.sinks).IsZero()
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
g.It("does not remove any sinks when the channel does not match", func() {
ch := make(chan []byte, 1)
ch2 := make(chan []byte, 1)
pool.On(ch)
g.Assert(len(pool.sinks)).Equal(1)
pool.Off(ch2)
g.Assert(len(pool.sinks)).Equal(1)
g.Assert(pool.sinks[0]).Equal(ch)
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
g.It("removes a channel and maintains the order", func() {
channels := make([]chan []byte, 8)
for i := 0; i < len(channels); i++ {
channels[i] = make(chan []byte, 1)
pool.On(channels[i])
}
g.Assert(len(pool.sinks)).Equal(8)
pool.Off(channels[2])
g.Assert(len(pool.sinks)).Equal(7)
g.Assert(pool.sinks[1]).Equal(channels[1])
g.Assert(pool.sinks[2]).Equal(channels[3])
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
g.It("does not panic if a nil channel is provided", func() {
ch := make([]chan []byte, 1)
defer func () {
if r := recover(); r != nil {
g.Fail("removing a nil channel should not cause a panic")
}
}()
pool.On(ch[0])
pool.Off(ch[0])
g.Assert(len(pool.sinks)).Equal(0)
})
})
g.Describe("SinkPool#Push", func() {
var pool *sinkPool
g.BeforeEach(func() {
pool = &sinkPool{}
})
g.It("works when no sinks are registered", func() {
g.Assert(len(pool.sinks)).IsZero()
pool.Push([]byte("test"))
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
g.It("sends data to every registered sink", func() {
ch1 := make(chan []byte, 1)
ch2 := make(chan []byte, 1)
pool.On(ch1)
pool.On(ch2)
g.Assert(len(pool.sinks)).Equal(2)
b := []byte("test")
pool.Push(b)
g.Assert(MutexLocked(&pool.mu)).IsFalse()
g.Assert(<-ch1).Equal(b)
g.Assert(<-ch2).Equal(b)
g.Assert(len(pool.sinks)).Equal(2)
})
g.It("does not block if a channel is nil or otherwise full", func() {
ch := make([]chan []byte, 2)
ch[1] = make(chan []byte, 1)
ch[1] <- []byte("test")
pool.On(ch[0])
pool.On(ch[1])
pool.Push([]byte("testing"))
g.Assert(MutexLocked(&pool.mu)).IsFalse()
g.Assert(<-ch[1]).Equal([]byte("test"))
pool.Push([]byte("test2"))
g.Assert(<-ch[1]).Equal([]byte("test2"))
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
})
g.Describe("SinkPool#Destroy", func() {
var pool *sinkPool
g.BeforeEach(func() {
pool = &sinkPool{}
})
g.It("works if no sinks are registered", func() {
pool.Destroy()
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
g.It("closes all channels fully", func() {
ch1 := make(chan []byte, 1)
ch2 := make(chan []byte, 1)
pool.On(ch1)
pool.On(ch2)
g.Assert(len(pool.sinks)).Equal(2)
pool.Destroy()
g.Assert(pool.sinks).IsZero()
defer func() {
r := recover()
g.Assert(r).IsNotNil()
g.Assert(r.(error).Error()).Equal("send on closed channel")
}()
ch1 <- []byte("test")
})
g.It("works when a sink channel is nil", func() {
ch := make([]chan []byte, 2)
pool.On(ch[0])
pool.On(ch[1])
pool.Destroy()
g.Assert(MutexLocked(&pool.mu)).IsFalse()
})
})
}