JSON deserialization failed during integration tests for bitbucket server 4.6.x

Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 22.148 sec <<< FAILURE!
it.com.pbaranchikov.stash.checks.CreateBranchTest  Time elapsed: 22.148 sec  <<< ERROR!
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected an int but was BEGIN_OBJECT at line 1 column 26 path $.testResult.fCount
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:221)
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:117)
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:217)
        at com.google.gson.Gson.fromJson(Gson.java:861)
        at com.google.gson.Gson.fromJson(Gson.java:826)
        at com.google.gson.Gson.fromJson(Gson.java:775)
        at com.google.gson.Gson.fromJson(Gson.java:747)
        at com.atlassian.plugins.osgi.test.AtlassianPluginsTestRunner.runViaRestCall(AtlassianPluginsTestRunner.java:118)
        at com.atlassian.plugins.osgi.test.AtlassianPluginsTestRunner.run(AtlassianPluginsTestRunner.java:75)
        at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
        at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
        at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
        at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
        at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
        at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)
Caused by: java.lang.IllegalStateException: Expected an int but was BEGIN_OBJECT at line 1 column 26 path $.testResult.fCount
        at com.google.gson.stream.JsonReader.nextInt(JsonReader.java:1201)
        at com.google.gson.internal.bind.TypeAdapters$8.read(TypeAdapters.java:263)
        at com.google.gson.internal.bind.TypeAdapters$8.read(TypeAdapters.java:260)
        at com.google.gson.TypeAdapter$1.read(TypeAdapter.java:199)
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:117)
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:217)
        ... 20 more