diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 00000000..6a2a792b
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,68 @@
+# novelWriter Tests
+
+The test suite uses PyTest for testing.
+
+## Dependencies
+
+* `python3-pytest` for the basic framework (required)
+* `python3-pytestqt` for Qt support (required)
+* `python3-pytest-cov` for code coverage reports (optional)
+* `python3-pytest-xvfb` for headless tests (optional)
+
+## HowTo
+
+### Basic Usage
+
+To run all tests, type:
+```bash
+pytest-3 -v
+```
+
+The `-v` switch enables verbose mode, with one test per line.
+For a more compact view, omit this switch.
+
+### Headless
+
+To run tests in headless mode, either use the Qt `offscreen` mode:
+```bash
+export QT_QPA_PLATFORM=offscreen
+```
+
+or run with `xvfb`:
+```bash
+xvfb-run pytest-3 -v
+```
+
+### Test Coverage
+
+To add test coverage, run the following:
+```bash
+pytest-3 -v --cov=nw --cov-report=html
+```
+
+The `--cov-report` switch generates an html report, omit it to print a coverage summary to the terminal.
+The html coverage report will be available in the `htmlcov` folder.
+
+### Test Markers (Categories)
+
+To run with specific test markers, add the `-m` switch:
+```bash
+pytest-3 -v -m core
+```
+
+Available markers are:
+
+* '`core`' for test covering the classes in the `nw/core` folder
+
+## Tests
+
+To filter specific groups of tests, use the `-k` switch.
+The commands for the respective test categories are listed below.
+
+| Type | Test Target    | Source File(s)   | Marker    | Filter             |
+| :--- | :------------- | :--------------- | :-------- | :----------------- |
+| Unit | Core functions | nw/core/tools.py | `-m core` | `-k testCoreTools` |
+| Unit | NWIndex class  | nw/core/index.py | `-m core` | `-k testCoreIndex` |
+| Unit | NWItem class   | nw/core/item.py  | `-m core` | `-k testCoreItem`  |
+| Unit | NWTree class   | nw/core/tree.py  | `-m core` | `-k testCoreTree`  |
+
diff --git a/tests/conftest.py b/tests/conftest.py
index 2d2ec6e8..0e59a3dc 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -26,12 +26,12 @@ def tmpDir():
     be checked. The folder is instead cleared before a new test session.
     """
     testDir = os.path.dirname(__file__)
-    tempDir = os.path.join(testDir, "temp")
-    if os.path.isdir(tempDir):
-        shutil.rmtree(tempDir)
-    if not os.path.isdir(tempDir):
-        os.mkdir(tempDir)
-    return tempDir
+    theDir = os.path.join(testDir, "temp")
+    if os.path.isdir(theDir):
+        shutil.rmtree(theDir)
+    if not os.path.isdir(theDir):
+        os.mkdir(theDir)
+    return theDir
 
 @pytest.fixture(scope="session")
 def refDir():
@@ -39,8 +39,17 @@ def refDir():
     the results of tests.
     """
     testDir = os.path.dirname(__file__)
-    refDir = os.path.join(testDir, "reference")
-    return refDir
+    theDir = os.path.join(testDir, "reference")
+    return theDir
+
+@pytest.fixture(scope="session")
+def outDir(tmpDir):
+    """An output folder for test results
+    """
+    theDir = os.path.join(tmpDir, "results")
+    if not os.path.isdir(theDir):
+        os.mkdir(theDir)
+    return theDir
 
 ##
 #  novelWriter Objects
diff --git a/tests/test_core_index.py b/tests/test_core_index.py
index 74bdd899..1d577b70 100644
--- a/tests/test_core_index.py
+++ b/tests/test_core_index.py
@@ -15,12 +15,12 @@ from nw.core.index import NWIndex
 from nw.constants import nwItemClass, nwItemLayout
 
 @pytest.mark.core
-def testCoreIndex_LoadSave(monkeypatch, nwLipsum, dummyGUI, nwTempProj, refDir):
+def testCoreIndex_LoadSave(monkeypatch, nwLipsum, dummyGUI, outDir, refDir):
     """Test core functionality of scaning, saving, loading and checking
     the index cache file.
     """
     projFile = os.path.join(nwLipsum, "meta", "tagsIndex.json")
-    testFile = os.path.join(nwTempProj, "coreIndex_LoadSave_tagsIndex.json")
+    testFile = os.path.join(outDir, "coreIndex_LoadSave_tagsIndex.json")
     compFile = os.path.join(refDir, "coreIndex_LoadSave_tagsIndex.json")
 
     theProject = NWProject(dummyGUI)