diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 00000000..2515d6b9
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,6 @@
+[run]
+branch = True
+
+[report]
+exclude_lines =
+    raise NotImplementedError
diff --git a/.gitignore b/.gitignore
index 371aa15d..40361e9f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,16 +1,18 @@
 _trial_temp
 build
 build-pypy
 MANIFEST
 dist
 apidocs
 *,cover
 .testrepository
 *.pyc
 *.so
 *~
 *.swp
 docs/tutorial/index.html
 dulwich.egg-info/
 .tox/
 .idea/
+.coverage
+htmlcov/
diff --git a/Makefile b/Makefile
index 0e265eb4..dee0a3cb 100644
--- a/Makefile
+++ b/Makefile
@@ -1,60 +1,67 @@
 PYTHON = python
 PYFLAKES = pyflakes
 PEP8 = pep8
 SETUP = $(PYTHON) setup.py
 PYDOCTOR ?= pydoctor
 TESTRUNNER ?= unittest
 RUNTEST = PYTHONHASHSEED=random PYTHONPATH=.:$(PYTHONPATH) $(PYTHON) -m $(TESTRUNNER) $(TEST_OPTIONS)
+COVERAGE = python3-coverage
 
 DESTDIR=/
 
 all: build
 
 doc:: pydoctor
 doc:: sphinx
 
 sphinx::
 	$(MAKE) -C docs html
 
 pydoctor::
 	$(PYDOCTOR) --make-html -c dulwich.cfg
 
 build::
 	$(SETUP) build
 	$(SETUP) build_ext -i
 
 install::
 	$(SETUP) install --root="$(DESTDIR)"
 
 check:: build
 	$(RUNTEST) dulwich.tests.test_suite
 
 check-tutorial:: build
 	$(RUNTEST) dulwich.tests.tutorial_test_suite
 
 check-nocompat:: build
 	$(RUNTEST) dulwich.tests.nocompat_test_suite
 
 check-compat:: build
 	$(RUNTEST) dulwich.tests.compat_test_suite
 
 check-pypy:: clean
 	$(MAKE) check-noextensions PYTHON=pypy
 
 check-noextensions:: clean
 	$(RUNTEST) dulwich.tests.test_suite
 
 check-all: check check-pypy check-noextensions
 
 clean::
 	$(SETUP) clean --all
 	rm -f dulwich/*.so
 
 flakes:
 	$(PYFLAKES) dulwich
 
 pep8:
 	$(PEP8) dulwich
 
 before-push: check
 	git diff origin/master | $(PEP8) --diff
+
+coverage:
+	$(COVERAGE) run --source=dulwich -m unittest dulwich.tests.test_suite dulwich.contrib.test_suite
+
+coverage-html: coverage
+	$(COVERAGE) html