Add proper exit code check to mypy script.

.travis.yml

@@ -8,7 +8,10 @@ install:
   - "pip install -r requirements.dev.txt"
 
 script:
+  # Run the test suit
   - nosetests --with-coverage --cover-package=stegano
+  # Run the type checker
+  - python tools/run_mypy.py
 
 after_success:
   - coveralls

tools/run_mypy.py

@@ -0,0 +1,18 @@
+import subprocess
+import sys
+
+modules = ["stegano/tools.py",
+            "stegano/lsb/lsb.py",
+            "stegano/lsbset/lsbset.py",
+            "stegano/lsbset/generators.py",
+            "stegano/red/red.py",
+            "stegano/exifHeader/exifHeader.py",
+            "stegano/steganalysis/parity.py",
+            "stegano/steganalysis/statistics.py"]
+
+exit_codes = []
+for module in modules:
+    rc = subprocess.call(["mypy", "--ignore-missing-imports",
+                          "--follow-imports", "skip", module])
+    exit_codes.append(rc)
+sys.exit(max(exit_codes))