[FAB-10768] Fix a bug in couchdb version cache

This CR fixes a bug in couchdb version cache

Change-Id: Iba6f5177dcedc2edf9541f4849384a73d9b51f2c
Signed-off-by: manish <manish.sethi@gmail.com>

Author: manish-sethi

core/ledger/kvledger/txmgmt/statedb/statecouchdb/version_cache.go

@@ -28,9 +28,9 @@ func newVersionCache() *versionsCache {
 }
 
 func (c *versionsCache) getVersion(ns, key string) (*version.Height, bool) {
-	nsVers, ok := c.vers[ns]
+	ver, ok := c.vers[ns][key]
 	if ok {
-		return nsVers[key], true
+		return ver, true
 	}
 	return nil, false
 }

core/ledger/kvledger/txmgmt/statedb/statecouchdb/version_cache_test.go

@@ -0,0 +1,37 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package statecouchdb
+
+import (
+	"testing"
+
+	"github.com/hyperledger/fabric/core/ledger/kvledger/txmgmt/version"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestVersionCache(t *testing.T) {
+	verCache := newVersionCache()
+	ver1 := version.NewHeight(1, 1)
+	ver2 := version.NewHeight(2, 2)
+	verCache.setVerAndRev("ns1", "key1", version.NewHeight(1, 1), "rev1")
+	verCache.setVerAndRev("ns2", "key2", version.NewHeight(2, 2), "rev2")
+
+	ver, found := verCache.getVersion("ns1", "key1")
+	assert.True(t, found)
+	assert.Equal(t, ver1, ver)
+
+	ver, found = verCache.getVersion("ns2", "key2")
+	assert.True(t, found)
+	assert.Equal(t, ver2, ver)
+
+	ver, found = verCache.getVersion("ns1", "key3")
+	assert.False(t, found)
+	assert.Nil(t, ver)
+
+	ver, found = verCache.getVersion("ns3", "key4")
+	assert.False(t, found)
+	assert.Nil(t, ver)
+}