Add an unsafe memory discovery store for testing.

Signed-off-by: David Calavera <david.calavera@gmail.com>

discovery/memory/memory_test.go

@@ -0,0 +1,48 @@
+package memory
+
+import (
+	"testing"
+
+	"github.com/docker/docker/pkg/discovery"
+	"github.com/go-check/check"
+)
+
+// Hook up gocheck into the "go test" runner.
+func Test(t *testing.T) { check.TestingT(t) }
+
+type discoverySuite struct{}
+
+var _ = check.Suite(&discoverySuite{})
+
+func (s *discoverySuite) TestWatch(c *check.C) {
+	d := &Discovery{}
+	d.Initialize("foo", 1000, 0, nil)
+	stopCh := make(chan struct{})
+	ch, errCh := d.Watch(stopCh)
+
+	// We have to drain the error channel otherwise Watch will get stuck.
+	go func() {
+		for range errCh {
+		}
+	}()
+
+	expected := discovery.Entries{
+		&discovery.Entry{Host: "1.1.1.1", Port: "1111"},
+	}
+
+	c.Assert(d.Register("1.1.1.1:1111"), check.IsNil)
+	c.Assert(<-ch, check.DeepEquals, expected)
+
+	expected = discovery.Entries{
+		&discovery.Entry{Host: "1.1.1.1", Port: "1111"},
+		&discovery.Entry{Host: "2.2.2.2", Port: "2222"},
+	}
+
+	c.Assert(d.Register("2.2.2.2:2222"), check.IsNil)
+	c.Assert(<-ch, check.DeepEquals, expected)
+
+	// Stop and make sure it closes all channels.
+	close(stopCh)
+	c.Assert(<-ch, check.IsNil)
+	c.Assert(<-errCh, check.IsNil)
+}