Make 'tc --test' exit code indicate PASS or FAIL

taxcalc/cli/tc.py

@@ -133,9 +133,11 @@ def main():
                  output_sqldb=args.sqldb)
     # compare test output with expected test output if --test option specified
     if args.test:
-        compare_test_output_files()
-    # return no-error exit code
-    return 0
+        retcode = compare_test_output_files()
+    else:
+        retcode = 0
+    # return exit code
+    return retcode
 # end of main function code
 
 
@@ -165,18 +167,22 @@ def write_test_input_output_files():
 
 def compare_test_output_files():
     """
-    Compare expected and actual test output files.
+    Compare expected and actual test output files;
+    returns 0 if pass test, otherwise returns 1.
     """
     explines = open(EXPECTED_TEST_OUTPUT_FILENAME, 'U').readlines()
     actlines = open(ACTUAL_TEST_OUTPUT_FILENAME, 'U').readlines()
     if ''.join(explines) == ''.join(actlines):
         sys.stdout.write('PASSED TEST\n')
+        retcode = 0
     else:
+        retcode = 1
         sys.stdout.write('FAILED TEST\n')
         diff = difflib.unified_diff(explines, actlines,
                                     fromfile=EXPECTED_TEST_OUTPUT_FILENAME,
                                     tofile=ACTUAL_TEST_OUTPUT_FILENAME, n=0)
         sys.stdout.writelines(diff)
+    return retcode
 
 
 if __name__ == '__main__':

taxcalc/tests/test_parameters.py

@@ -10,8 +10,8 @@
 import six
 import numpy as np
 import pytest
-from taxcalc import ParametersBase  # pylint: disable=import-error
-from taxcalc import Policy, Consumption  # pylint: disable=import-error
+# pylint: disable=import-error
+from taxcalc import ParametersBase, Policy, Consumption
 
 
 def test_instantiation_and_usage():