diff --git a/main/commons-test/pom.xml b/main/commons-test/pom.xml
index c8ff86ead..bba69fa84 100644
--- a/main/commons-test/pom.xml
+++ b/main/commons-test/pom.xml
@@ -18,6 +18,10 @@
 			<groupId>junit</groupId>
 			<artifactId>junit</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>de.bechte.junit</groupId>
+			<artifactId>junit-hierarchicalcontextrunner</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.hamcrest</groupId>
 			<artifactId>hamcrest-all</artifactId>
diff --git a/main/filesystem-api/src/main/java/org/cryptomator/filesystem/Copier.java b/main/filesystem-api/src/main/java/org/cryptomator/filesystem/Copier.java
index 442124889..ff790d73d 100644
--- a/main/filesystem-api/src/main/java/org/cryptomator/filesystem/Copier.java
+++ b/main/filesystem-api/src/main/java/org/cryptomator/filesystem/Copier.java
@@ -18,7 +18,7 @@ class Copier {
 
 		source.files().forEach(sourceFile -> {
 			File destinationFile = destination.file(sourceFile.name());
-			copy(sourceFile, destinationFile);
+			sourceFile.copyTo(destinationFile);
 		});
 
 		source.folders().forEach(sourceFolder -> {
@@ -27,6 +27,12 @@ class Copier {
 		});
 	}
 
+	public static void copy(File source, File destination) {
+		try (OpenFiles openFiles = DeadlockSafeFileOpener.withReadable(source).andWritable(destination).open()) {
+			openFiles.readable(source).copyTo(openFiles.writable(destination));
+		}
+	}
+
 	private static void assertFoldersAreNotNested(Folder source, Folder destination) {
 		if (source.isAncestorOf(destination)) {
 			throw new IllegalArgumentException("Can not copy parent to child directory (src: " + source + ", dst: " + destination + ")");
@@ -36,10 +42,4 @@ class Copier {
 		}
 	}
 
-	public static void copy(File source, File destination) {
-		try (OpenFiles openFiles = DeadlockSafeFileOpener.withReadable(source).andWritable(destination).open()) {
-			openFiles.readable(source).copyTo(openFiles.writable(destination));
-		}
-	}
-
 }
diff --git a/main/filesystem-api/src/test/java/org/cryptomator/filesystem/CopierTest.java b/main/filesystem-api/src/test/java/org/cryptomator/filesystem/CopierTest.java
new file mode 100644
index 000000000..d32d1d231
--- /dev/null
+++ b/main/filesystem-api/src/test/java/org/cryptomator/filesystem/CopierTest.java
@@ -0,0 +1,173 @@
+package org.cryptomator.filesystem;
+
+import static java.util.Arrays.asList;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.stream.Stream;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+import de.bechte.junit.runners.context.HierarchicalContextRunner;
+
+@RunWith(HierarchicalContextRunner.class)
+public class CopierTest {
+
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
+	@Rule
+	public MockitoRule mockitoRule = MockitoJUnit.rule();
+
+	public class CopyFiles {
+
+		@Mock
+		private File source;
+
+		@Mock
+		private File destination;
+
+		@Test
+		public void testCopyFileOpensFilesInSortedOrderIfSourceIsSmallerDestination() {
+			mockCompareToWithOrder(source, destination);
+			when(source.openReadable()).thenReturn(mock(ReadableFile.class));
+			when(destination.openWritable()).thenReturn(mock(WritableFile.class));
+
+			Copier.copy(source, destination);
+
+			InOrder inOrder = inOrder(source, destination);
+			inOrder.verify(source).openReadable();
+			inOrder.verify(destination).openWritable();
+		}
+
+		@Test
+		public void testCopyFileOpensFilesInSortedOrderIfDestinationIsSmallerSource() {
+			mockCompareToWithOrder(destination, source);
+			when(source.openReadable()).thenReturn(mock(ReadableFile.class));
+			when(destination.openWritable()).thenReturn(mock(WritableFile.class));
+
+			Copier.copy(source, destination);
+
+			InOrder inOrder = inOrder(source, destination);
+			inOrder.verify(destination).openWritable();
+			inOrder.verify(source).openReadable();
+		}
+
+		@Test
+		public void testCopyFileInvokesCopyToOnReadableSourceWithWritableDestintation() {
+			ReadableFile readableSource = mock(ReadableFile.class);
+			WritableFile writableDestination = mock(WritableFile.class);
+			mockCompareToWithOrder(source, destination);
+			when(source.openReadable()).thenReturn(readableSource);
+			when(destination.openWritable()).thenReturn(writableDestination);
+
+			Copier.copy(source, destination);
+
+			verify(readableSource).copyTo(writableDestination);
+		}
+
+		private void mockCompareToWithOrder(File first, File last) {
+			when(first.compareTo(last)).thenReturn(-1);
+			when(last.compareTo(first)).thenReturn(1);
+		}
+
+	}
+
+	public class CopyFolders {
+
+		@Mock
+		private Folder source;
+
+		@Mock
+		private Folder destination;
+
+		@Test
+		public void testCopyFolderDeletesAndCreatesDestinationBeforeIteratingOverTheFilesAndFoldersInSource() {
+			when(source.files()).thenReturn(Stream.empty());
+			when(source.folders()).thenReturn(Stream.empty());
+
+			Copier.copy(source, destination);
+
+			InOrder inOrder = inOrder(source, destination);
+			inOrder.verify(destination).delete();
+			inOrder.verify(destination).create();
+			inOrder.verify(source).files();
+			inOrder.verify(source).folders();
+		}
+
+		@Test
+		@SuppressWarnings({ "unchecked", "rawtypes" })
+		public void testCopyFolderInvokesCopyToOnAllFilesInSourceWithFileWithSameNameFromDestination() {
+			String filename1 = "nameOfFile1";
+			String filename2 = "nameOfFile2";
+			File file1 = mock(File.class);
+			File file2 = mock(File.class);
+			File destinationFile1 = mock(File.class);
+			File destinationFile2 = mock(File.class);
+			when(source.files()).thenReturn((Stream) asList(file1, file2).stream());
+			when(source.folders()).thenReturn(Stream.empty());
+			when(destination.file(filename1)).thenReturn(destinationFile1);
+			when(destination.file(filename2)).thenReturn(destinationFile2);
+			when(file1.name()).thenReturn(filename1);
+			when(file2.name()).thenReturn(filename2);
+
+			Copier.copy(source, destination);
+
+			verify(file1).copyTo(destinationFile1);
+			verify(file2).copyTo(destinationFile2);
+		}
+
+		@Test
+		@SuppressWarnings({ "unchecked", "rawtypes" })
+		public void testCopyFolderInvokesCopyToOnAllFoldersInSourceWithFolderWithSameNameFromDestination() {
+			String folderName1 = "nameOfFolder1";
+			String folderName2 = "nameOfFolder2";
+			Folder folder1 = mock(Folder.class);
+			Folder folder2 = mock(Folder.class);
+			Folder destinationfolder1 = mock(Folder.class);
+			Folder destinationfolder2 = mock(Folder.class);
+			when(source.folders()).thenReturn((Stream) asList(folder1, folder2).stream());
+			when(source.files()).thenReturn(Stream.empty());
+			when(destination.folder(folderName1)).thenReturn(destinationfolder1);
+			when(destination.folder(folderName2)).thenReturn(destinationfolder2);
+			when(folder1.name()).thenReturn(folderName1);
+			when(folder2.name()).thenReturn(folderName2);
+
+			Copier.copy(source, destination);
+
+			verify(folder1).copyTo(destinationfolder1);
+			verify(folder2).copyTo(destinationfolder2);
+		}
+
+		@Test
+		public void testCopyFolderFailsWithIllegalArgumentExceptionIfSourceIsNestedInDestination() {
+			when(source.isAncestorOf(destination)).thenReturn(false);
+			when(destination.isAncestorOf(source)).thenReturn(true);
+
+			thrown.expect(IllegalArgumentException.class);
+
+			Copier.copy(source, destination);
+		}
+
+		@Test
+		public void testCopyFolderFailsWithIllegalArgumentExceptionIfDestinationIsNestedInSource() {
+			when(source.isAncestorOf(destination)).thenReturn(true);
+			when(destination.isAncestorOf(source)).thenReturn(false);
+
+			thrown.expect(IllegalArgumentException.class);
+
+			Copier.copy(source, destination);
+		}
+
+	}
+
+}
diff --git a/main/pom.xml b/main/pom.xml
index db046a3de..6b8ad2b48 100644
--- a/main/pom.xml
+++ b/main/pom.xml
@@ -31,6 +31,7 @@
 		<log4j.version>2.1</log4j.version>
 		<slf4j.version>1.7.7</slf4j.version>
 		<junit.version>4.12</junit.version>
+		<junit.hierarchicalrunner.version>4.12.1</junit.hierarchicalrunner.version>
 		<hamcrest.version>1.3</hamcrest.version> <!-- keep in sync with version required by JUnit -->
 		<commons-io.version>2.4</commons-io.version>
 		<commons-collections.version>4.0</commons-collections.version>
@@ -197,6 +198,11 @@
 					</exclusion>
 				</exclusions>
 			</dependency>
+			<dependency>
+				<groupId>de.bechte.junit</groupId>
+				<artifactId>junit-hierarchicalcontextrunner</artifactId>
+				<version>${junit.hierarchicalrunner.version}</version>
+			</dependency>
 			<dependency>
 				<groupId>org.mockito</groupId>
 				<artifactId>mockito-core</artifactId>