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Diffstat (limited to 'vendor/github.com/golang/groupcache/groupcache_test.go')
| -rw-r--r-- | vendor/github.com/golang/groupcache/groupcache_test.go | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/vendor/github.com/golang/groupcache/groupcache_test.go b/vendor/github.com/golang/groupcache/groupcache_test.go new file mode 100644 index 000000000..3a4ecc2cc --- /dev/null +++ b/vendor/github.com/golang/groupcache/groupcache_test.go @@ -0,0 +1,447 @@ +/* +Copyright 2012 Google Inc. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +// Tests for groupcache. + +package groupcache + +import ( + "errors" + "fmt" + "hash/crc32" + "math/rand" + "reflect" + "sync" + "testing" + "time" + + "github.com/golang/protobuf/proto" + + pb "github.com/golang/groupcache/groupcachepb" + testpb "github.com/golang/groupcache/testpb" +) + +var ( + once sync.Once + stringGroup, protoGroup Getter + + stringc = make(chan string) + + dummyCtx Context + + // cacheFills is the number of times stringGroup or + // protoGroup's Getter have been called. Read using the + // cacheFills function. + cacheFills AtomicInt +) + +const ( + stringGroupName = "string-group" + protoGroupName = "proto-group" + testMessageType = "google3/net/groupcache/go/test_proto.TestMessage" + fromChan = "from-chan" + cacheSize = 1 << 20 +) + +func testSetup() { + stringGroup = NewGroup(stringGroupName, cacheSize, GetterFunc(func(_ Context, key string, dest Sink) error { + if key == fromChan { + key = <-stringc + } + cacheFills.Add(1) + return dest.SetString("ECHO:" + key) + })) + + protoGroup = NewGroup(protoGroupName, cacheSize, GetterFunc(func(_ Context, key string, dest Sink) error { + if key == fromChan { + key = <-stringc + } + cacheFills.Add(1) + return dest.SetProto(&testpb.TestMessage{ + Name: proto.String("ECHO:" + key), + City: proto.String("SOME-CITY"), + }) + })) +} + +// tests that a Getter's Get method is only called once with two +// outstanding callers. This is the string variant. +func TestGetDupSuppressString(t *testing.T) { + once.Do(testSetup) + // Start two getters. The first should block (waiting reading + // from stringc) and the second should latch on to the first + // one. + resc := make(chan string, 2) + for i := 0; i < 2; i++ { + go func() { + var s string + if err := stringGroup.Get(dummyCtx, fromChan, StringSink(&s)); err != nil { + resc <- "ERROR:" + err.Error() + return + } + resc <- s + }() + } + + // Wait a bit so both goroutines get merged together via + // singleflight. + // TODO(bradfitz): decide whether there are any non-offensive + // debug/test hooks that could be added to singleflight to + // make a sleep here unnecessary. + time.Sleep(250 * time.Millisecond) + + // Unblock the first getter, which should unblock the second + // as well. + stringc <- "foo" + + for i := 0; i < 2; i++ { + select { + case v := <-resc: + if v != "ECHO:foo" { + t.Errorf("got %q; want %q", v, "ECHO:foo") + } + case <-time.After(5 * time.Second): + t.Errorf("timeout waiting on getter #%d of 2", i+1) + } + } +} + +// tests that a Getter's Get method is only called once with two +// outstanding callers. This is the proto variant. +func TestGetDupSuppressProto(t *testing.T) { + once.Do(testSetup) + // Start two getters. The first should block (waiting reading + // from stringc) and the second should latch on to the first + // one. + resc := make(chan *testpb.TestMessage, 2) + for i := 0; i < 2; i++ { + go func() { + tm := new(testpb.TestMessage) + if err := protoGroup.Get(dummyCtx, fromChan, ProtoSink(tm)); err != nil { + tm.Name = proto.String("ERROR:" + err.Error()) + } + resc <- tm + }() + } + + // Wait a bit so both goroutines get merged together via + // singleflight. + // TODO(bradfitz): decide whether there are any non-offensive + // debug/test hooks that could be added to singleflight to + // make a sleep here unnecessary. + time.Sleep(250 * time.Millisecond) + + // Unblock the first getter, which should unblock the second + // as well. + stringc <- "Fluffy" + want := &testpb.TestMessage{ + Name: proto.String("ECHO:Fluffy"), + City: proto.String("SOME-CITY"), + } + for i := 0; i < 2; i++ { + select { + case v := <-resc: + if !reflect.DeepEqual(v, want) { + t.Errorf(" Got: %v\nWant: %v", proto.CompactTextString(v), proto.CompactTextString(want)) + } + case <-time.After(5 * time.Second): + t.Errorf("timeout waiting on getter #%d of 2", i+1) + } + } +} + +func countFills(f func()) int64 { + fills0 := cacheFills.Get() + f() + return cacheFills.Get() - fills0 +} + +func TestCaching(t *testing.T) { + once.Do(testSetup) + fills := countFills(func() { + for i := 0; i < 10; i++ { + var s string + if err := stringGroup.Get(dummyCtx, "TestCaching-key", StringSink(&s)); err != nil { + t.Fatal(err) + } + } + }) + if fills != 1 { + t.Errorf("expected 1 cache fill; got %d", fills) + } +} + +func TestCacheEviction(t *testing.T) { + once.Do(testSetup) + testKey := "TestCacheEviction-key" + getTestKey := func() { + var res string + for i := 0; i < 10; i++ { + if err := stringGroup.Get(dummyCtx, testKey, StringSink(&res)); err != nil { + t.Fatal(err) + } + } + } + fills := countFills(getTestKey) + if fills != 1 { + t.Fatalf("expected 1 cache fill; got %d", fills) + } + + g := stringGroup.(*Group) + evict0 := g.mainCache.nevict + + // Trash the cache with other keys. + var bytesFlooded int64 + // cacheSize/len(testKey) is approximate + for bytesFlooded < cacheSize+1024 { + var res string + key := fmt.Sprintf("dummy-key-%d", bytesFlooded) + stringGroup.Get(dummyCtx, key, StringSink(&res)) + bytesFlooded += int64(len(key) + len(res)) + } + evicts := g.mainCache.nevict - evict0 + if evicts <= 0 { + t.Errorf("evicts = %v; want more than 0", evicts) + } + + // Test that the key is gone. + fills = countFills(getTestKey) + if fills != 1 { + t.Fatalf("expected 1 cache fill after cache trashing; got %d", fills) + } +} + +type fakePeer struct { + hits int + fail bool +} + +func (p *fakePeer) Get(_ Context, in *pb.GetRequest, out *pb.GetResponse) error { + p.hits++ + if p.fail { + return errors.New("simulated error from peer") + } + out.Value = []byte("got:" + in.GetKey()) + return nil +} + +type fakePeers []ProtoGetter + +func (p fakePeers) PickPeer(key string) (peer ProtoGetter, ok bool) { + if len(p) == 0 { + return + } + n := crc32.Checksum([]byte(key), crc32.IEEETable) % uint32(len(p)) + return p[n], p[n] != nil +} + +// tests that peers (virtual, in-process) are hit, and how much. +func TestPeers(t *testing.T) { + once.Do(testSetup) + rand.Seed(123) + peer0 := &fakePeer{} + peer1 := &fakePeer{} + peer2 := &fakePeer{} + peerList := fakePeers([]ProtoGetter{peer0, peer1, peer2, nil}) + const cacheSize = 0 // disabled + localHits := 0 + getter := func(_ Context, key string, dest Sink) error { + localHits++ + return dest.SetString("got:" + key) + } + testGroup := newGroup("TestPeers-group", cacheSize, GetterFunc(getter), peerList) + run := func(name string, n int, wantSummary string) { + // Reset counters + localHits = 0 + for _, p := range []*fakePeer{peer0, peer1, peer2} { + p.hits = 0 + } + + for i := 0; i < n; i++ { + key := fmt.Sprintf("key-%d", i) + want := "got:" + key + var got string + err := testGroup.Get(dummyCtx, key, StringSink(&got)) + if err != nil { + t.Errorf("%s: error on key %q: %v", name, key, err) + continue + } + if got != want { + t.Errorf("%s: for key %q, got %q; want %q", name, key, got, want) + } + } + summary := func() string { + return fmt.Sprintf("localHits = %d, peers = %d %d %d", localHits, peer0.hits, peer1.hits, peer2.hits) + } + if got := summary(); got != wantSummary { + t.Errorf("%s: got %q; want %q", name, got, wantSummary) + } + } + resetCacheSize := func(maxBytes int64) { + g := testGroup + g.cacheBytes = maxBytes + g.mainCache = cache{} + g.hotCache = cache{} + } + + // Base case; peers all up, with no problems. + resetCacheSize(1 << 20) + run("base", 200, "localHits = 49, peers = 51 49 51") + + // Verify cache was hit. All localHits are gone, and some of + // the peer hits (the ones randomly selected to be maybe hot) + run("cached_base", 200, "localHits = 0, peers = 49 47 48") + resetCacheSize(0) + + // With one of the peers being down. + // TODO(bradfitz): on a peer number being unavailable, the + // consistent hashing should maybe keep trying others to + // spread the load out. Currently it fails back to local + // execution if the first consistent-hash slot is unavailable. + peerList[0] = nil + run("one_peer_down", 200, "localHits = 100, peers = 0 49 51") + + // Failing peer + peerList[0] = peer0 + peer0.fail = true + run("peer0_failing", 200, "localHits = 100, peers = 51 49 51") +} + +func TestTruncatingByteSliceTarget(t *testing.T) { + var buf [100]byte + s := buf[:] + if err := stringGroup.Get(dummyCtx, "short", TruncatingByteSliceSink(&s)); err != nil { + t.Fatal(err) + } + if want := "ECHO:short"; string(s) != want { + t.Errorf("short key got %q; want %q", s, want) + } + + s = buf[:6] + if err := stringGroup.Get(dummyCtx, "truncated", TruncatingByteSliceSink(&s)); err != nil { + t.Fatal(err) + } + if want := "ECHO:t"; string(s) != want { + t.Errorf("truncated key got %q; want %q", s, want) + } +} + +func TestAllocatingByteSliceTarget(t *testing.T) { + var dst []byte + sink := AllocatingByteSliceSink(&dst) + + inBytes := []byte("some bytes") + sink.SetBytes(inBytes) + if want := "some bytes"; string(dst) != want { + t.Errorf("SetBytes resulted in %q; want %q", dst, want) + } + v, err := sink.view() + if err != nil { + t.Fatalf("view after SetBytes failed: %v", err) + } + if &inBytes[0] == &dst[0] { + t.Error("inBytes and dst share memory") + } + if &inBytes[0] == &v.b[0] { + t.Error("inBytes and view share memory") + } + if &dst[0] == &v.b[0] { + t.Error("dst and view share memory") + } +} + +// orderedFlightGroup allows the caller to force the schedule of when +// orig.Do will be called. This is useful to serialize calls such +// that singleflight cannot dedup them. +type orderedFlightGroup struct { + mu sync.Mutex + stage1 chan bool + stage2 chan bool + orig flightGroup +} + +func (g *orderedFlightGroup) Do(key string, fn func() (interface{}, error)) (interface{}, error) { + <-g.stage1 + <-g.stage2 + g.mu.Lock() + defer g.mu.Unlock() + return g.orig.Do(key, fn) +} + +// TestNoDedup tests invariants on the cache size when singleflight is +// unable to dedup calls. +func TestNoDedup(t *testing.T) { + const testkey = "testkey" + const testval = "testval" + g := newGroup("testgroup", 1024, GetterFunc(func(_ Context, key string, dest Sink) error { + return dest.SetString(testval) + }), nil) + + orderedGroup := &orderedFlightGroup{ + stage1: make(chan bool), + stage2: make(chan bool), + orig: g.loadGroup, + } + // Replace loadGroup with our wrapper so we can control when + // loadGroup.Do is entered for each concurrent request. + g.loadGroup = orderedGroup + + // Issue two idential requests concurrently. Since the cache is + // empty, it will miss. Both will enter load(), but we will only + // allow one at a time to enter singleflight.Do, so the callback + // function will be called twice. + resc := make(chan string, 2) + for i := 0; i < 2; i++ { + go func() { + var s string + if err := g.Get(dummyCtx, testkey, StringSink(&s)); err != nil { + resc <- "ERROR:" + err.Error() + return + } + resc <- s + }() + } + + // Ensure both goroutines have entered the Do routine. This implies + // both concurrent requests have checked the cache, found it empty, + // and called load(). + orderedGroup.stage1 <- true + orderedGroup.stage1 <- true + orderedGroup.stage2 <- true + orderedGroup.stage2 <- true + + for i := 0; i < 2; i++ { + if s := <-resc; s != testval { + t.Errorf("result is %s want %s", s, testval) + } + } + + const wantItems = 1 + if g.mainCache.items() != wantItems { + t.Errorf("mainCache has %d items, want %d", g.mainCache.items(), wantItems) + } + + // If the singleflight callback doesn't double-check the cache again + // upon entry, we would increment nbytes twice but the entry would + // only be in the cache once. + const wantBytes = int64(len(testkey) + len(testval)) + if g.mainCache.nbytes != wantBytes { + t.Errorf("cache has %d bytes, want %d", g.mainCache.nbytes, wantBytes) + } +} + +// TODO(bradfitz): port the Google-internal full integration test into here, +// using HTTP requests instead of our RPC system. |