diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2eb8d0f..53b55cc 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,16 +9,17 @@ phonemizer-build:
     - conda create --name phonemizer-ci python=3 2> /dev/null || true
     - conda activate phonemizer-ci
 
-    # install the phonemizer
-    - pip install coverage
-    - python setup.py build
+    # install dependencies for testing
+    - pip install --upgrade pytest coverage
+
+    # install phonemizer
     - python setup.py install
 
 .phonemizer-test: &phonemizer-test
 # run the unit tests within the CI environment
 - conda activate phonemizer-ci
 - phonemize --version
-- python setup.py test
+- coverage run && coverage report
 
 phonemizer-test-espeak-1-48-04:
   stage: test
diff --git a/.travis.yml b/.travis.yml
index 6e26c6e..05cc9ca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,15 +20,15 @@ before_install:
 
 install:
   - pip install --upgrade pip
-  - pip install pytest-cov codecov joblib segments
-  - python setup.py build
   - python setup.py install
+  - pip install --upgrade pytest coverage codecov
 
 script:
   - phonemize --version
-  - python setup.py test
+  - pytest
 
 after_success:
+  - coverage run
   - codecov
 
 cache:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b02ecb5..4b25823 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 Version numbers follow [semantic versioning](https://semver.org)
 
+## not yet released
+
+* **bugfixes**
+
+  Fixed installation from source (bug introduced in 2.2.1, see
+  issue [#52](https://github.com/bootphon/phonemizer/issues/52).
+
 ## phonemizer-2.2.1
 
 * **improvements**
diff --git a/Dockerfile b/Dockerfile
index 97667f3..ab0bad6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 # Use this file to build a docker image of phonemizer (using
-# festival-2.5 and espeak-ng-1.49.2 from ubuntu repo):
+# festival-2.5.0 and espeak-ng-1.50 from ubuntu repo):
 #
 #    sudo docker build -t phonemizer .
 #
@@ -12,11 +12,11 @@
 
 
 # Use an official Ubuntu as a parent image
-FROM ubuntu:18.04
+FROM ubuntu:20.04
 
 ENV LANG=C.UTF-8 LC_ALL=C.UTF-8
 
-# Set the working directory to /phonemizer
+# set the working directory to /phonemizer
 WORKDIR /phonemizer
 
 # install dependencies
@@ -30,15 +30,17 @@ RUN apt-get update && apt-get upgrade -y && apt-get install -y \
         python3-pip && \
     apt-get clean
 
-# Pytest needs to be installed through pip to make sure we have a recent version
-RUN pip3 install pytest pytest-cov
+# pytest needs to be installed through pip to make sure we have a recent version
+RUN pip3 install pytest
 
-# Tests expect python to be available as executable 'python' not 'python3'
+# tests expect python to be available as executable 'python' not 'python3'
 RUN ln -s /usr/bin/python3 /usr/bin/python
 
+# copy the phonemizer code within the docker image
+COPY . /phonemizer
+
 # install phonemizer and run the tests
-RUN git clone https://github.com/bootphon/phonemizer.git && \
-    cd phonemizer && \
+RUN cd /phonemizer && \
     python3 setup.py install && \
     phonemize --version && \
     python3 -m pytest -v test
diff --git a/README.md b/README.md
index 147583c..6457f16 100644
--- a/README.md
+++ b/README.md
@@ -66,9 +66,7 @@ the phonemizer.
 
         $ git clone https://github.com/bootphon/phonemizer
         $ cd phonemizer
-        $ python setup.py build
         $ [sudo] python setup.py install
-        $ python setup.py test  # optionally run the tests
 
   If you experiment an error such as `ImportError: No module named
   setuptools` during installation, refeer to [issue
@@ -89,6 +87,15 @@ Then run an interactive session with:
     $ sudo docker run -it phonemizer /bin/bash
 
 
+### Testing
+
+When installed from sources or whithin a Docker image, you can run the tests
+suite from the root `phonemizer` folder (once you installed `pytest`):
+
+    $ pip install pytest
+    $ pytest
+
+
 ## Python usage
 
 In Python import the `phonemize` function with `from phonemizer import
diff --git a/phonemizer/__init__.py b/phonemizer/__init__.py
index 217f81d..73e4224 100644
--- a/phonemizer/__init__.py
+++ b/phonemizer/__init__.py
@@ -14,6 +14,21 @@
 # along with phonologizer. If not, see <http://www.gnu.org/licenses/>.
 """Multilingual text to phones converter"""
 
-from .phonemize import phonemize
 
 __version__ = '2.2.1'
+
+
+try:  # pragma: nocover
+    # This variable is injected in the __builtins__ by the build process. In
+    # that case we don't want to import phonemize as there are missing
+    # dependencies.
+    __PHONEMIZER_SETUP__
+except NameError:
+    __PHONEMIZER_SETUP__ = False
+
+
+if __PHONEMIZER_SETUP__:  # pragma: nocover
+    import sys
+    sys.stderr.write('Partial import of phonemizer during the build process.\n')
+else:
+    from .phonemize import phonemize
diff --git a/setup.cfg b/setup.cfg
index 427cf1d..a09d993 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,15 +1,22 @@
-[aliases]
-test=pytest
-
 [tool:pytest]
-addopts = --verbose --doctest-modules --cov=phonemizer --cov-report=html --cov-report=term:skip-covered
+minversion = 5.0
 testpaths = test
 python_files = test/*.py
+filterwarnings =
+    # ignore some deprecation warnings (on regexp escape sequence) for segments
+    # module and its dependencies
+    ignore::DeprecationWarning:.*segments.*
+    ignore::DeprecationWarning:.*csvw.*
+    ignore::DeprecationWarning:.*clldutils.*
 
 [build_sphinx]
 source-dir = doc/source
 build-dir = doc/build
 
+[coverage:run]
+command_line = -m pytest
+source = phonemizer
+
 [coverage:report]
 exclude_lines =
     pragma: nocover
diff --git a/setup.py b/setup.py
index 153046b..954015a 100755
--- a/setup.py
+++ b/setup.py
@@ -16,10 +16,20 @@
 # along with phonemizer. If not, see <http://www.gnu.org/licenses/>.
 """Setup script for the phonemizer package"""
 
+import builtins
 import codecs
 import setuptools
+
+
+# This is a bit hackish: we are setting a global variable so that the main
+# phonemizer __init__ can detect if it is being loaded by the setup routine, to
+# avoid attempting to load components that aren't built yet.
+builtins.__PHONEMIZER_SETUP__ = True
+
+
 import phonemizer
 
+
 setuptools.setup(
     # general description
     name='phonemizer',
@@ -28,8 +38,6 @@
 
     # python package dependancies
     install_requires=['joblib', 'segments', 'attrs>=18.1'],
-    setup_requires=['pytest-runner'],
-    tests_require=['pytest', 'pytest-cov'],
 
     # include Python code and any files in phonemizer/share
     packages=setuptools.find_packages(),