...
Component | Behavior in | Behavior in TestServer |
|---|---|---|
SQL, HTTP and KV layers | identical | |
Coordination glue around SQL/HTTP/KV to create an overall running server ( | identical | |
Server configuration | Via CLI flags, defaults useful for production deployments. | via Via For example, KV storage is in-RAM by default (no persistence) to make tests faster. There is also a predefined TLS configuration with a self-signed CA. |
Of note, cockroach demo uses TestServer under the hood so all the properties and limitations of TestServer apply to cockroach demo as well.
Introduction to TestServer and TestCluster in Go unit tests
...
| Code Block | ||
|---|---|---|
| ||
func TestSomething(t *testing.T) {
defer leaktest.AfterTest()() // verify no goroutine leaks
defer log.Scope(t).Close(t) // capture test logs intelligently
ctx := context.Background()
srv := serverutils.StartServerOnly(t, base.TestServerArgs{}) // initialize and start a TestServer
defer srv.Stopper().Stop(ctx) // ensure the TestServer gets cleaned up at the end of the test
ts := srv.ApplicationLayer() // see below for an explanation
// ... use ts in test code ... |
Alternatively, the following is also possible:
| Code Block | ||
|---|---|---|
| ||
srv, db, kvDB := serverutils.StartServer(t, base.TestServerArgs{}) |
as it is equivalent to:
| Code Block | ||
|---|---|---|
| ||
srv := serverutils.StartServerOnly(t, base.TestServerArgs{}) db := srv.ApplicationLayer().SQLConn(t, "") // access to SQL kvDB := srv.ApplicationLayer().DB() // access to KV |
When a test needs to exercise a cluster of 2 or more nodes connected together, it can use TestCluster:
| Code Block | ||
|---|---|---|
| ||
func TestSomething(t *testing.T) { defer leaktest.AfterTest()() // verify no goroutine leaks defer log.Scope(t).Close(t) // capture test logs intelligently ctx := context.Background() const numNodes = 3 tc := serverutils.StartCluster(t, numNodes, base.TestClusterArgs{}) // initialize and start a TestCluster defer tc.Stopper().Stop(ctx) // ensure the TestCluster gets cleaned up at the end of the test ts0 := tc.Server(0).ApplicationLayer() // see below for an explanation ts1 := tc.Server(1).ApplicationLayer() // see below for an explanation // ... use ts0 and ts1 in test code ... |
In a nutshell, the result of StartCluster (TestClusterInterface) has a Server(nodeIdx) method which returns a different TestServer for each node in the simulated cluster.
Note: there is no benefit to using StartCluster with just 1 node. Prefer StartServer in that case.
High-level TestServer API
Let’s inspect the interface of Serverutils.StartServerOnly():
| Code Block | ||
|---|---|---|
| ||
func StartServerOnly(t TestFataler, params base.TestServerArgs) TestServerInterface type TestServerInterface interface { TestServerController // ApplicationLayer returns the interface to the application layer that is // exercised by the test. ApplicationLayer() ApplicationLayerInterface // SystemLayer returns the interface to the application layer // of the system tenant. SystemLayer() ApplicationLayerInterface // StorageLayer returns the interface to the storage layer. StorageLayer() StorageLayerInterface ... } // TestServerController defines the control interface for a test server. type TestServerController interface { ... // Stopper returns the stopper used by the server. Stopper() *stop.Stopper ... } // ApplicationLayerInterface defines accessors to the application // layer of a test server. type ApplicationLayerInterface interface { ... // SQLConn returns a handle to the server's SQL interface, opened // with the 'root' user. // The connection is closed automatically when the server is stopped. SQLConn(t TestFataler, dbName 𝓢) *gosql.DB ... } // StorageLayerInterface defines accessors to the storage layer of a // test server. See ApplicationLayerInterface for the relevant // application-level APIs. type StorageLayerInterface interface { ... // LookupRange looks up the range descriptor which contains key. LookupRange(key roachpb.Key) (roachpb.RangeDescriptor, ⊙) ... } |