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|
package cache
import (
"context"
"errors"
"sync"
"sync/atomic"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
type client struct {
resolutions uint64
domain chan string
failure error
status int
}
func (c *client) Resolve(ctx context.Context, _ string) Lookup {
atomic.AddUint64(&c.resolutions, 1)
if c.status == 0 {
c.status = 200
}
if c.failure != nil {
return Lookup{Domain: Domain{}, Status: c.status, Error: c.failure}
}
return Lookup{Domain: Domain{Name: <-c.domain}, Status: c.status, Error: nil}
}
func withTestCache(config resolverConfig, block func(*Cache, *client)) {
var resolver *client
if config.buffered {
resolver = &client{domain: make(chan string, 1), failure: config.failure}
} else {
resolver = &client{domain: make(chan string), failure: config.failure}
}
cache := NewCache(resolver)
block(cache, resolver)
}
func (cache *Cache) withTestEntry(config entryConfig, block func()) {
domain := "my.gitlab.com"
if len(config.domain) > 0 {
domain = config.domain
}
entry := cache.store.ReplaceOrCreate(context.Background(), domain)
if config.retrieved {
newResponse := make(chan Lookup, 1)
newResponse <- Lookup{Domain: Domain{Name: domain}, Status: 200}
entry.setResponse(newResponse)
}
if config.expired {
entry.created = time.Now().Add(-time.Hour)
}
block()
}
type resolverConfig struct {
buffered bool
failure error
}
type entryConfig struct {
domain string
expired bool
retrieved bool
}
func TestResolve(t *testing.T) {
t.Run("when item is not cached", func(t *testing.T) {
withTestCache(resolverConfig{buffered: true}, func(cache *Cache, resolver *client) {
resolver.domain <- "my.gitlab.com"
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.NoError(t, lookup.Error)
assert.Equal(t, 200, lookup.Status)
assert.Equal(t, "my.gitlab.com", lookup.Domain.Name)
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
t.Run("when item is not cached and accessed multiple times", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
wg := &sync.WaitGroup{}
ctx := context.Background()
receiver := func() {
defer wg.Done()
cache.Resolve(ctx, "my.gitlab.com")
}
wg.Add(3)
go receiver()
go receiver()
go receiver()
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
wg.Wait()
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
t.Run("when item is in short cache", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: false, retrieved: true}, func() {
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, "my.gitlab.com", lookup.Domain.Name)
assert.Equal(t, uint64(0), resolver.resolutions)
})
})
})
t.Run("when item is in long cache only", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: true, retrieved: true}, func() {
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, "my.gitlab.com", lookup.Domain.Name)
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
})
t.Run("when item in long cache is requested multiple times", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: true, retrieved: true}, func() {
cache.Resolve(context.Background(), "my.gitlab.com")
cache.Resolve(context.Background(), "my.gitlab.com")
cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
})
t.Run("when retrieval failed with an error", func(t *testing.T) {
withTestCache(resolverConfig{failure: errors.New("500 err")}, func(cache *Cache, resolver *client) {
maxRetrievalInterval = 0
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, uint64(3), resolver.resolutions)
assert.EqualError(t, lookup.Error, "500 err")
})
})
t.Run("when retrieval failed because of an external context timeout", func(t *testing.T) {
ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(-time.Hour))
defer cancel()
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
lookup := cache.Resolve(ctx, "my.gitlab.com")
assert.Equal(t, uint64(0), resolver.resolutions)
assert.EqualError(t, lookup.Error, "context timeout")
})
})
t.Run("when retrieval failed because of an internal context timeout", func(t *testing.T) {
retrievalTimeout = 0
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, uint64(0), resolver.resolutions)
assert.EqualError(t, lookup.Error, "context timeout")
})
})
}
|
