Ensure we use MockSystemReader in tests

If we use the default system reader FileStoreAttributes cannot persist
attributes in userConfig when tests run in Bazel due to sandboxing.
Hence we need to ensure that all tests use MockSystemReader (and
especially a mocked userConfig).

Change-Id: Ic1ad8e2ec5a150c5433434a5f6667d6c4674c87d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.lfs.server.test/tst/org/eclipse/jgit/lfs/server/fs/LfsServerTest.java

@@ -74,6 +74,7 @@ import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.eclipse.jetty.servlet.ServletHolder;
+import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.junit.http.AppServer;
 import org.eclipse.jgit.lfs.errors.LfsException;
 import org.eclipse.jgit.lfs.lib.AnyLongObjectId;
@@ -85,6 +86,7 @@ import org.eclipse.jgit.lfs.test.LongObjectIdTestUtils;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.IO;
+import org.eclipse.jgit.util.SystemReader;
 import org.junit.After;
 import org.junit.Before;
 
@@ -119,6 +121,7 @@ public abstract class LfsServerTest {
 
 	@Before
 	public void setup() throws Exception {
+		SystemReader.setInstance(new MockSystemReader());
 		tmp = Files.createTempDirectory("jgit_test_");
 
 		// measure timer resolution before the test to avoid time critical tests

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/FileSnapshotTest.java

@@ -62,6 +62,7 @@ import java.time.Instant;
 import java.util.ArrayList;
 import java.util.concurrent.TimeUnit;
 
+import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FS.FileStoreAttributes;
 import org.eclipse.jgit.util.FileUtils;
@@ -84,6 +85,7 @@ public class FileSnapshotTest {
 
 	@Before
 	public void setUp() throws Exception {
+		SystemReader.setInstance(new MockSystemReader());
 		trash = Files.createTempDirectory("tmp_");
 		// measure timer resolution before the test to avoid time critical tests
 		// are affected by time needed for measurement

org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/FileBasedConfigTest.java

@@ -55,9 +55,11 @@ import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 
 import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.IO;
+import org.eclipse.jgit.util.SystemReader;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -82,6 +84,7 @@ public class FileBasedConfigTest {
 
 	@Before
 	public void setUp() throws Exception {
+		SystemReader.setInstance(new MockSystemReader());
 		trash = Files.createTempDirectory("tmp_");
 		FS.getFileStoreAttributes(trash.getParent());
 	}