Added travis notifications only on fail (#2091)

* Added travis notifications only on fail

* fixup! Format Python code with psf/black push

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

.travis.yml

@@ -7,6 +7,7 @@ before_install: pip install --upgrade pip setuptools six
 install: pip install black flake8
 notifications:
     webhooks: https://www.travisbuddy.com/
+    on_success: never
 before_script:
   - black --check . || true
   - flake8 --ignore=E203,W503 --max-complexity=25 --max-line-length=120 --statistics --count .

greedy_method/test_knapsack.py

@@ -67,7 +67,9 @@ class TestClass(unittest.TestCase):
         # profit = [10, 20, 30, 40, 50]
         # weight = [2, 4, 6, 8, 10, 12]
         # max_weight = 100
-        self.assertRaisesRegex(IndexError, "The length of profit and weight must be same.")
+        self.assertRaisesRegex(
+            IndexError, "The length of profit and weight must be same."
+        )
 
 
 if __name__ == "__main__":