Add a make file for dev tasks.

Makefile

@@ -0,0 +1,22 @@
+PYTHON ?= python3
+
+.PHONY: help
+help:  ## Print help about available targets.
+	@grep -h -E '^[a-zA-Z0-9_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}'
+
+.PHONY: depends
+depends:
+	$(PYTHON) -m pip install flake8
+	$(PYTHON) -m pip install coverage
+
+.PHONY: lint
+lint:
+	$(PYTHON) -m flake8 --ignore E24,E121,E123,E125,E126,E221,E226,E266,E704,E265 $(CURDIR)
+
+.PHONY: test
+test: ## Run the test suite.
+	$(PYTHON) -m tests
+
+.PHONY: coverage
+coverage:  ## Check line coverage.
+	$(PYTHON) -m coverage run -m tests