made the pylint2 and pylint3 tests faster

Makefile

@@ -2,28 +2,31 @@
 
 IGNORED_PYLINT_TESTS=invalid-name missing-docstring \
 	redefined-variable-type too-few-public-methods
-IGNORED_PYLINT2_TESTS=superfluous-parens
-IGNORED_PYLINT3_TESTS=
+IGNORED_PYLINT2_TESTS=superfluous-parens duplicate-code
+IGNORED_PYLINT3_TESTS=duplicate-code
 
 tests:
+	# all tests
 	@make -j 3 output pylint2 pylint3
-	# all ok
+	# all tests ok
 
 output:
-	# testing python script output
+	# python output test
 	@set -e; \
 	TEMP=`mktemp`; \
 	trap 'rm $$TEMP' EXIT; \
 	for FILE in *.py; do \
-		printf 'output test:\t%s\n' "$$FILE"; \
+		printf '# python output test "%s"\n' "$$FILE"; \
 		if [ -e "$$FILE.out" ]; then \
 			python "$$FILE" > $$TEMP; \
 			diff "$$FILE.out" $$TEMP; \
+			printf '# python output test "%s" ok\n' "$$FILE"; \
 		else \
 			printf 'No output test exists for file "%s".\n' "$$FILE"; \
 			exit 1; \
 		fi; \
 	done
+	# python output test ok
 
 COMMA:=,
 EMPTY:=
@@ -34,23 +37,15 @@ PYLINT3_OPTIONS=--disable=$(subst $(SPACE),$(COMMA),\
 	$(IGNORED_PYLINT_TESTS) $(IGNORED_PYLINT3_TESTS))
 
 pylint2:
-	# testing python scripts via pylint2
-	@for FILE in *.py; do \
-		printf 'pylint2 test:\t%s\n' "$$FILE"; \
-		REPORT="$$(pylint $(PYLINT2_OPTIONS) "$$FILE" 2>&1)"; \
-		if ! [ $$? = 0 ]; then \
-			printf '%s\nThe above report is for file "%s".\n' "$$REPORT" "$$FILE"; \
-			exit 1; \
-		fi; \
-	done
+	# pylint2 test
+	@if ! REPORT="$$(pylint $(PYLINT2_OPTIONS) *.py 2>&1)"; then \
+		printf "%s\n" "$$REPORT"; \
+	fi
+	# pylint2 test ok
 
 pylint3:
-	# testing python scripts via pylint3
-	@for FILE in *.py; do \
-		printf 'pylint3 test:\t%s\n' "$$FILE"; \
-		REPORT="$$(pylint3 $(PYLINT3_OPTIONS) "$$FILE" 2>&1)"; \
-		if ! [ $$? = 0 ]; then \
-			printf '%s\nThe above report is for file "%s".\n' "$$REPORT" "$$FILE"; \
-			exit 1; \
-		fi; \
-	done
+	# pylint3 test
+	@if ! REPORT="$$(pylint3 $(PYLINT3_OPTIONS) *.py 2>&1)"; then \
+		printf "%s\n" "$$REPORT"; \
+	fi
+	# pylint3 test ok