diff --git a/.github/workflows/osx.yml b/.github/workflows/osx.yml
index f386a74b37..64a61bcf73 100644
--- a/.github/workflows/osx.yml
+++ b/.github/workflows/osx.yml
@@ -29,5 +29,5 @@ jobs:
         make develop
     - name: Test Mathics
       run: |
-        pip install pytest pexpect
+        pip install -r requirements-dev.txt
         make -j3 check
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index c3d9fb7d06..921bb8f1ab 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -28,5 +28,5 @@ jobs:
         make develop
     - name: Test Mathics
       run: |
-        pip install pytest pexpect
+        pip install -r requirements-dev.txt
         make -j3 check
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 7d38df6cc3..869d75d03c 100755
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -31,5 +31,6 @@ jobs:
         python setup.py install
     - name: Test Mathics
       run: |
-        pip install pytest
+        pip install -r requirements-dev.txt
+        set PYTEST_WORKERS="-n3"
         make check
diff --git a/Makefile b/Makefile
index dd7aaac44d..607d3162e1 100644
--- a/Makefile
+++ b/Makefile
@@ -57,7 +57,7 @@ clean:
 
 #: Run py.test tests. Use environment variable "o" for pytest options
 pytest:
-	py.test test $o
+	py.test $(PYTEST_WORKERS) test $o
 
 
 #: Run a more extensive pattern-matching test
diff --git a/mathics/builtin/logic.py b/mathics/builtin/logic.py
index 23c86cb236..0a0e2f5a1d 100644
--- a/mathics/builtin/logic.py
+++ b/mathics/builtin/logic.py
@@ -320,8 +320,8 @@ def apply(self, args, evaluation):
 class True_(Predefined):
     """
     <dl>
-    <dt>'True'
-        <dd>represents the Boolean true value.
+      <dt>'True'
+      <dd>represents the Boolean true value.
     </dl>
     """
 
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 0000000000..63b622214c
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1,4 @@
+# Additional packages used in testing
+pytest
+pytest-xdist
+pexpect