diff --git a/setup.py b/setup.py
index f95aab5..a8363de 100755
--- a/setup.py
+++ b/setup.py
@@ -57,5 +57,5 @@ See http://propka.org/ for the PROPKA web server.
         },
       zip_safe=True,
       python_requires='>=3',
-      test_suite="Tests",
+      test_suite="tests",
 )
diff --git a/Tests/.gitignore b/tests/.gitignore
similarity index 100%
rename from Tests/.gitignore
rename to tests/.gitignore
diff --git a/Tests/__init__.py b/tests/__init__.py
similarity index 100%
rename from Tests/__init__.py
rename to tests/__init__.py
diff --git a/Tests/hybrid36.py b/tests/hybrid36.py
similarity index 100%
rename from Tests/hybrid36.py
rename to tests/hybrid36.py
diff --git a/Tests/pdb/1FTJ-Chain-A.pdb b/tests/pdb/1FTJ-Chain-A.pdb
similarity index 100%
rename from Tests/pdb/1FTJ-Chain-A.pdb
rename to tests/pdb/1FTJ-Chain-A.pdb
diff --git a/Tests/pdb/1HPX-warn.pdb b/tests/pdb/1HPX-warn.pdb
similarity index 100%
rename from Tests/pdb/1HPX-warn.pdb
rename to tests/pdb/1HPX-warn.pdb
diff --git a/Tests/pdb/1HPX.pdb b/tests/pdb/1HPX.pdb
similarity index 100%
rename from Tests/pdb/1HPX.pdb
rename to tests/pdb/1HPX.pdb
diff --git a/Tests/pdb/3SGB-subset.pdb b/tests/pdb/3SGB-subset.pdb
similarity index 100%
rename from Tests/pdb/3SGB-subset.pdb
rename to tests/pdb/3SGB-subset.pdb
diff --git a/Tests/pdb/3SGB.pdb b/tests/pdb/3SGB.pdb
similarity index 100%
rename from Tests/pdb/3SGB.pdb
rename to tests/pdb/3SGB.pdb
diff --git a/Tests/pdb/4DFR.pdb b/tests/pdb/4DFR.pdb
similarity index 100%
rename from Tests/pdb/4DFR.pdb
rename to tests/pdb/4DFR.pdb
diff --git a/Tests/pkacalc_test.py b/tests/pkacalc_test.py
similarity index 100%
rename from Tests/pkacalc_test.py
rename to tests/pkacalc_test.py
diff --git a/Tests/results/1FTJ-Chain-A.dat b/tests/results/1FTJ-Chain-A.dat
similarity index 100%
rename from Tests/results/1FTJ-Chain-A.dat
rename to tests/results/1FTJ-Chain-A.dat
diff --git a/Tests/results/1HPX-warn.dat b/tests/results/1HPX-warn.dat
similarity index 100%
rename from Tests/results/1HPX-warn.dat
rename to tests/results/1HPX-warn.dat
diff --git a/Tests/results/1HPX.dat b/tests/results/1HPX.dat
similarity index 100%
rename from Tests/results/1HPX.dat
rename to tests/results/1HPX.dat
diff --git a/Tests/results/3SGB-subset.dat b/tests/results/3SGB-subset.dat
similarity index 100%
rename from Tests/results/3SGB-subset.dat
rename to tests/results/3SGB-subset.dat
diff --git a/Tests/results/3SGB.dat b/tests/results/3SGB.dat
similarity index 100%
rename from Tests/results/3SGB.dat
rename to tests/results/3SGB.dat
diff --git a/Tests/results/4DFR.dat b/tests/results/4DFR.dat
similarity index 100%
rename from Tests/results/4DFR.dat
rename to tests/results/4DFR.dat
diff --git a/Tests/runtest.py b/tests/runtest.py
similarity index 100%
rename from Tests/runtest.py
rename to tests/runtest.py