feat(varlogtest): create new instance of admin and log (#591)

### What this PR does

This PR renames `pkg/varlogtest.(*VarlogTest).Admin` and `pkg/varlogtest.(*VarlogTest).Log` to `pkg/varlogtest.(*VarlogTest).NewAdminClient` and `pkg/varlogtest.(*VarlogTest).NewLogClient` respectively. It also makes them return a new instance of the admin client and the log client when invoked.
Previously, they returned the same instances, so callers shared them. However, it wasn't the right decision because the callers had to share the clients regardless of their needs.

pkg/varlogtest/admin.go

@@ -23,14 +23,15 @@ import (
 )
 
 type testAdmin struct {
-	vt *VarlogTest
+	vt     *VarlogTest
+	closed bool
 }
 
 var _ varlog.Admin = (*testAdmin)(nil)
 
 func (c *testAdmin) lock() error {
 	c.vt.cond.L.Lock()
-	if c.vt.adminClientClosed {
+	if c.closed {
 		c.vt.cond.L.Unlock()
 		return verrors.ErrClosed
 	}
@@ -534,6 +535,6 @@ func (c *testAdmin) RemoveMRPeer(ctx context.Context, raftURL string, opts ...va
 func (c *testAdmin) Close() error {
 	c.vt.cond.L.Lock()
 	defer c.vt.cond.L.Unlock()
-	c.vt.adminClientClosed = true
+	c.closed = true
 	return nil
 }

pkg/varlogtest/log.go

@@ -14,14 +14,15 @@ import (
 )
 
 type testLog struct {
-	vt *VarlogTest
+	vt     *VarlogTest
+	closed bool
 }
 
 var _ varlog.Log = (*testLog)(nil)
 
 func (c *testLog) lock() error {
 	c.vt.cond.L.Lock()
-	if c.vt.varlogClientClosed {
+	if c.closed {
 		c.vt.cond.L.Unlock()
 		return verrors.ErrClosed
 	}
@@ -35,7 +36,7 @@ func (c *testLog) unlock() {
 func (c *testLog) Close() error {
 	c.vt.cond.L.Lock()
 	defer c.vt.cond.L.Unlock()
-	c.vt.varlogClientClosed = true
+	c.closed = true
 	c.vt.cond.Broadcast()
 	return nil
 }
@@ -247,7 +248,7 @@ func (c *testLog) SubscribeTo(ctx context.Context, topicID types.TopicID, logStr
 		return logEntries
 	}
 	s.vt.closedClient = func() bool {
-		return c.vt.varlogClientClosed
+		return c.closed
 	}
 
 	s.wg.Add(1)

pkg/varlogtest/varlogtest.go

@@ -17,9 +17,6 @@ import (
 type VarlogTest struct {
 	config
 
-	admin *testAdmin
-	vlg   *testLog
-
 	rng *rand.Rand
 
 	mu               sync.Mutex
@@ -38,9 +35,6 @@ type VarlogTest struct {
 	nextTopicID       types.TopicID
 	nextStorageNodeID types.StorageNodeID
 	nextLogStreamID   types.LogStreamID
-
-	adminClientClosed  bool
-	varlogClientClosed bool
 }
 
 func New(opts ...Option) (*VarlogTest, error) {
@@ -62,8 +56,6 @@ func New(opts ...Option) (*VarlogTest, error) {
 		leaderMR:         types.InvalidNodeID,
 	}
 	vt.cond = sync.NewCond(&vt.mu)
-	vt.admin = &testAdmin{vt: vt}
-	vt.vlg = &testLog{vt: vt}
 
 	for _, mrn := range vt.initialMRNodes {
 		if vt.leaderMR == types.InvalidNodeID {
@@ -76,12 +68,12 @@ func New(opts ...Option) (*VarlogTest, error) {
 	return vt, nil
 }
 
-func (vt *VarlogTest) Admin() varlog.Admin {
-	return vt.admin
+func (vt *VarlogTest) NewAdminClient() varlog.Admin {
+	return &testAdmin{vt: vt}
 }
 
-func (vt *VarlogTest) Log() varlog.Log {
-	return vt.vlg
+func (vt *VarlogTest) NewLogClient() varlog.Log {
+	return &testLog{vt: vt}
 }
 
 func (vt *VarlogTest) generateTopicID() types.TopicID {

pkg/varlogtest/varlogtest_test.go

@@ -115,8 +115,8 @@ func TestVarlotTest_LogStreamAppender(t *testing.T) {
 			)
 			require.NoError(t, err)
 
-			adm := vt.Admin()
-			vlg := vt.Log()
+			adm := vt.NewAdminClient()
+			vlg := vt.NewLogClient()
 			defer func() {
 				require.NoError(t, vlg.Close())
 				require.NoError(t, adm.Close())
@@ -176,8 +176,8 @@ func TestVarlogTest(t *testing.T) {
 	)
 	require.NoError(t, err)
 
-	adm := vt.Admin()
-	vlg := vt.Log()
+	adm := vt.NewAdminClient()
+	vlg := vt.NewLogClient()
 	defer func() {
 		require.NoError(t, vlg.Close())
 		require.NoError(t, adm.Close())
@@ -594,8 +594,8 @@ func TestVarlogTest_Trim(t *testing.T) {
 	)
 	require.NoError(t, err)
 
-	adm := vt.Admin()
-	vlg := vt.Log()
+	adm := vt.NewAdminClient()
+	vlg := vt.NewLogClient()
 	defer func() {
 		require.NoError(t, vlg.Close())
 		require.NoError(t, adm.Close())
@@ -783,7 +783,7 @@ func TestVarlogTestAdminMetadataRepository(t *testing.T) {
 			)
 			require.NoError(t, err)
 
-			tc.testf(t, vt.Admin())
+			tc.testf(t, vt.NewAdminClient())
 		})
 	}
 }