GridCacheAbstractFullApiSelfTest.testWithSkipStore fails periodically on different configuration

junit.framework.AssertionFailedError: expected:<-1> but was:<21>
    at junit.framework.Assert.fail(Assert.java:57)
    at junit.framework.Assert.failNotEquals(Assert.java:329)
    at junit.framework.Assert.assertEquals(Assert.java:78)
    at junit.framework.Assert.assertEquals(Assert.java:86)
    at junit.framework.TestCase.assertEquals(TestCase.java:253)
    at org.apache.ignite.internal.processors.cache.GridCacheAbstractFullApiSelfTest.testWithSkipStore(GridCacheAbstractFullApiSelfTest.java:4534)
    at sun.reflect.GeneratedMethodAccessor108.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at junit.framework.TestCase.runTest(TestCase.java:176)
    at org.apache.ignite.testframework.junits.GridAbstractTest.runTestInternal(GridAbstractTest.java:1665)
    at org.apache.ignite.testframework.junits.GridAbstractTest.access$000(GridAbstractTest.java:111)
    at org.apache.ignite.testframework.junits.GridAbstractTest$6.run(GridAbstractTest.java:1603)