new: dev: increase coverage for rubix-presto module

[jordanw-bq]

Only test classes have been introduced, so testing on a Qubole cluster should not be required.

[jordanw-bq]

The Travis build is failing when trying to initialize the CachingPrestoS3FileSystem object. Seems to be an issue with a Java version mismatch (52.0 = Java 8). Could this be due to Rubix being compiled with Java 7, and Presto with Java 8?

java.lang.UnsupportedClassVersionError: com/facebook/presto/hive/PrestoS3FileSystem : Unsupported major.minor version 52.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:803)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:442)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:64)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:354)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:348)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:347)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:312)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:278)
    at sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:114)
    at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:125)
    at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
    at sun.reflect.generics.visitor.Reifier.reifyTypeArguments(Reifier.java:68)
    at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:138)
    at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
    at sun.reflect.generics.repository.ClassRepository.getSuperclass(ClassRepository.java:88)
    at java.lang.Class.getGenericSuperclass(Class.java:709)
    at com.qubole.rubix.core.CachingFileSystem.getTypeParameterClass(CachingFileSystem.java:75)
    at com.qubole.rubix.core.CachingFileSystem.<init>(CachingFileSystem.java:83)
    at com.qubole.rubix.presto.CachingPrestoS3FileSystem.<init>(CachingPrestoS3FileSystem.java:31)
    at com.qubole.rubix.presto.TestCachingPrestoS3FileSystem.testBasic(TestCachingPrestoS3FileSystem.java:31)

[coveralls]

Pull Request Test Coverage Report for Build 84

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 47 unchanged lines in 15 files lost coverage.
• Overall coverage increased (+0.1%) to 24.875%

---

Files with Coverage Reduction	New Missed Lines	%
rubix-bookkeeper/src/main/java/com/qubole/rubix/bookkeeper/FileDownloader.java	1	90.91%
rubix-spi/src/main/java/com/qubole/rubix/spi/DataTransferClientHelper.java	1	0.0%
rubix-core/src/main/java/com/qubole/rubix/core/RemoteFetchRequestChain.java	1	0.0%
rubix-bookkeeper/src/main/java/com/qubole/rubix/bookkeeper/LocalDataTransferServer.java	2	0.0%
rubix-core/src/main/java/com/qubole/rubix/core/CachedReadRequestChain.java	2	84.0%
rubix-core/src/main/java/com/qubole/rubix/core/DirectReadRequestChain.java	2	0.0%
rubix-bookkeeper/src/main/java/com/qubole/rubix/bookkeeper/BookKeeperServer.java	2	0.0%
rubix-bookkeeper/src/main/java/com/qubole/rubix/bookkeeper/utils/ShellExec.java	2	0.0%
rubix-core/src/main/java/com/qubole/rubix/core/CachingInputStream.java	3	0.0%
rubix-core/src/main/java/com/qubole/rubix/core/FileDownloadRequestChain.java	3	0.0%
<!--	Total:	47		-->

Totals
Change from base Build 81:	0.1%
Covered Lines:	548
Relevant Lines:	2203

---

💛 - Coveralls

[jordanw-bq]

Confirmed that the build passes when built using JDK 8

[vrajat]

I'll let others comment on the change to Java8

[shubhamtagra]

can we test hive with java7 and presto with java8?