diff --git a/tests/requirements-tools.txt b/tests/requirements-tools.txt
index 10a95643141..0069bedbe45 100644
--- a/tests/requirements-tools.txt
+++ b/tests/requirements-tools.txt
@@ -2,7 +2,7 @@
 git+https://github.com/pytest-dev/execnet.git
 
 # For running tests
-pytest  # pyup: >=2.7.3 # Testing framework.
+pytest==3.2.1  # pyup: >=2.7.3 # Testing framework.
 pytest-xdist==1.19.1     # Plugin allowing running tests in parallel.
 pytest-timeout==1.2.0   # Plugin to abort hanging tests.
 pytest-catchlog==1.2.2  # Capture log output separately from stdout/stderr