Unit tests fail during build

I have cloned the source and built using mvn clean package but the following tests are failing:

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T E S T S
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Running com.sforce.async.BulkConnectionTest
Tests run: 7, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.281 sec
Running com.sforce.async.CSVReaderTest
Tests run: 8, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.087 sec
Running com.sforce.ws.bind.XmlObjectTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.056 sec
Running com.sforce.ws.codegen.AggregateCodeGeneratorTest
Tests run: 2, Failures: 2, Errors: 0, Skipped: 0, Time elapsed: 0.146 sec <<< FAILURE!
Running com.sforce.ws.codegen.ComplexTypeCodeGeneratorTest
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.171 sec <<< FAILURE!
Running com.sforce.ws.codegen.ConnectionCodeGeneratorTest
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.155 sec <<< FAILURE!
Running com.sforce.ws.codegen.ConnectorCodeGeneratorTest
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.123 sec <<< FAILURE!
Running com.sforce.ws.codegen.SimpleTypeCodeGeneratorTest
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.131 sec <<< FAILURE!
Running com.sforce.ws.codegen.SObjectCodeGeneratorTest
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.128 sec <<< FAILURE!
Running com.sforce.ws.codegen.ToStringTest
[WSC][ForkedBooter.main:69]Generating Java files from schema ...
[WSC][ForkedBooter.main:69]Generated 5 java files.
[WSC][ForkedBooter.main:69]Compiling to target 1.6...
warning: [options] bootstrap class path not set in conjunction with -source 1.6
1 warning
[WSC][ForkedBooter.main:69]Compiled 7 java files.
[WSC][ForkedBooter.main:69]Generating jar file ... C:\Users\Jonathan\AppData\Local\Temp\ToStringTest7819659284299660405\test.jar
[WSC][ForkedBooter.main:69]Generated jar file C:\Users\Jonathan\AppData\Local\Temp\ToStringTest7819659284299660405\test.jar
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 5.716 sec
Running com.sforce.ws.codegen.VoidReturnTest
[WSC][ForkedBooter.main:69]Generating Java files from schema ...
[WSC][ForkedBooter.main:69]Generated 2 java files.
[WSC][ForkedBooter.main:69]Compiling to target 1.6...
warning: [options] bootstrap class path not set in conjunction with -source 1.6
1 warning
[WSC][ForkedBooter.main:69]Compiled 4 java files.
[WSC][ForkedBooter.main:69]Generating jar file ... C:\Users\Jonathan\AppData\Local\Temp\VoidReturnTest233323531517833232\test.jar
[WSC][ForkedBooter.main:69]Generated jar file C:\Users\Jonathan\AppData\Local\Temp\VoidReturnTest233323531517833232\test.jar
Tests run: 2, Failures: 1, Errors: 1, Skipped: 0, Time elapsed: 1.827 sec <<< FAILURE!
Running com.sforce.ws.transport.SoapConnectionTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.073 sec

Results :

Failed tests:

Tests in error:

Tests run: 30, Failures: 8, Errors: 1, Skipped: 0

I am running the following versions:

$ mvn -v
Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T16:41:47+00:00)
Maven home: C:\Users\Jonathan\Downloads\apache-maven-3.3.9-bin\apache-maven-3.3.9
Java version: 1.7.0_80, vendor: Oracle Corporation
Java home: C:\Program Files\Java\jdk1.7.0_80\jre
Default locale: en_GB, platform encoding: Cp1252
OS name: "windows 8.1", version: "6.3", arch: "amd64", family: "windows"