diff --git a/.travis.yml b/.travis.yml
index 03ba1706..fca46a13 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,6 +16,7 @@ matrix:
     script:
       - pytest test --cov;
     after_success:
+      - env
       - bash <(curl -s https://codecov.io/bash)
   - name: "Pytest python 3.6 with skggm"
     python: "3.6"
@@ -27,6 +28,7 @@ matrix:
     script:
       - pytest test --cov;
     after_success:
+      - env
       - bash <(curl -s https://codecov.io/bash)
   - name: "Pytest python 3.7 with skggm"
     python: "3.7"
@@ -38,6 +40,7 @@ matrix:
     script:
       - pytest test --cov;
     after_success:
+      - env
       - bash <(curl -s https://codecov.io/bash)
   - name: "Pytest python 3.6 with skggm + scikit-learn 0.20.3"
     # checks that tests work for the oldest supported scikit-learn version
@@ -51,6 +54,7 @@ matrix:
     script:
       - pytest test --cov;
     after_success:
+      - env
       - bash <(curl -s https://codecov.io/bash)
   - name: "Syntax checking with flake8"
     python: "3.7"
diff --git a/metric_learn/covariance.py b/metric_learn/covariance.py
index 3b218e6d..dabd2228 100644
--- a/metric_learn/covariance.py
+++ b/metric_learn/covariance.py
@@ -47,6 +47,10 @@ def fit(self, X, y=None):
     """
     X = self._prepare_inputs(X, ensure_min_samples=2)
     M = np.atleast_2d(np.cov(X, rowvar=False))
+    tt = 1+1
+    tt_bis = tt + 2
+    tt = tt_bis - 1
+    del(tt)
     if M.size == 1:
       M = 1. / M
     else: