diff --git a/.pyup.yml b/.pyup.yml
index 0c85ee8e03..04937ed0b0 100644
--- a/.pyup.yml
+++ b/.pyup.yml
@@ -4,21 +4,15 @@
 schedule: every month
 
 requirements:
-  - requirements.txt:
-      pin: False
-      update: False
-  - requirements_test.txt:
-      pin: False
-      update: False
-  - requirements_rtfd.txt:
-      pin: False
-      update: False
-  - requirements_dev.txt:
+  - requirements_dev_minimal.txt:
       pin: True
       update: all
-  - requirements_dev_npy.txt:
+  - requirements_dev_numpy.txt:
       pin: True
       update: all
   - requirements_dev_optional.txt:
       pin: True
       update: all
+  - requirements_rtfd.txt:
+      pin: False
+      update: False
diff --git a/.travis.yml b/.travis.yml
index 2c73212d0e..13618a50f5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,12 @@ addons:
     packages:
     - libdb-dev
 
+env:
+  global:
+    - ZARR_TEST_ABS=1
+    - ZARR_TEST_MONGO=1
+    - ZARR_TEST_REDIS=1
+
 services:
   - docker
   - redis-server
diff --git a/appveyor.yml b/appveyor.yml
index d04417d671..45c5a8af7a 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -14,6 +14,7 @@ environment:
     # See: http://stackoverflow.com/a/13751649/163740
     CMD_IN_ENV: "cmd /E:ON /V:ON /C .\\build.cmd"
     EMULATOR_LOC: C:\\Program Files (x86)\\Microsoft SDKs\\Azure\\Storage Emulator\\AzureStorageEmulator.exe
+    ZARR_TEST_ABS: 1
 
   matrix:
 
@@ -33,9 +34,7 @@ environment:
 install:
   - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
   - "%CMD_IN_ENV% python -m pip install -U pip setuptools wheel"
-  - "%CMD_IN_ENV% python -m pip install -rrequirements_test.txt"
-  - "%CMD_IN_ENV% python -m pip install -rrequirements_dev_npy.txt"
-  - "%CMD_IN_ENV% python -m pip install --no-binary=numcodecs -rrequirements_dev.txt"
+  - "%CMD_IN_ENV% python -m pip install -r requirements_dev_numpy.txt -r requirements_dev_minimal.txt -r requirements_dev_optional.txt"
   - "%CMD_IN_ENV% python setup.py install"
   - "%CMD_IN_ENV% python -m pip freeze"
 
@@ -43,6 +42,7 @@ build: off
 
 before_test:
   - '"%EMULATOR_LOC%" start'
+  - '"%EMULATOR_LOC%" status'
 
 test_script:
   - "%CMD_IN_ENV% python -m pytest -v --pyargs zarr"
diff --git a/docs/contributing.rst b/docs/contributing.rst
index af897d1963..e0c2ca5d88 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -90,10 +90,9 @@ you have cloned the Zarr source code and your current working directory is the r
 the repository, you can do something like the following::
 
     $ mkdir -p ~/pyenv/zarr-dev
-    $ virtualenv --no-site-packages --python=/usr/bin/python3.6 ~/pyenv/zarr-dev
+    $ virtualenv --no-site-packages --python=/usr/bin/python3.7 ~/pyenv/zarr-dev
     $ source ~/pyenv/zarr-dev/bin/activate
-    $ pip install -r requirements_dev.txt
-    $ pip install -r requirements_dev_optional.txt
+    $ pip install -r requirements_dev_minimal.txt -r requirements_dev_numpy.txt
     $ pip install -e .
 
 To verify that your development environment is working, you can run the unit tests::
@@ -139,34 +138,44 @@ Again, any conflicts need to be resolved before submitting a pull request.
 Running the test suite
 ~~~~~~~~~~~~~~~~~~~~~~
 
-Zarr includes a suite of unit tests, as well as doctests included in function and class
-docstrings and in the tutorial and storage spec. The simplest way to run the unit tests
-is to invoke::
+Zarr includes a suite of unit tests, as well as doctests included in
+function and class docstrings and in the tutorial and storage
+spec. The simplest way to run the unit tests is to activate your
+development environment (see `creating a development environment`_ above)
+and invoke::
 
     $ pytest -v zarr
 
-To also run the doctests within docstrings, run::
-
-    $ pytest -v --doctest-modules zarr
+Some tests require optional dependencies to be installed, otherwise
+the tests will be skipped. To install all optional dependencies, run::
 
-To run the doctests within the tutorial and storage spec, run::
+    $ pip install -r requirements_dev_optional.txt
 
-    $ python -m doctest -o NORMALIZE_WHITESPACE -o ELLIPSIS docs/tutorial.rst docs/spec/v2.rst
+To also run the doctests within docstrings (requires optional
+depencies to be installed), run::
 
-Tests can be run under different Python versions using tox. E.g. (assuming you have the
-corresponding Python interpreters installed on your system)::
+    $ pytest -v --doctest-plus zarr
 
-    $ tox -e py27,py34,py35,py36
+To run the doctests within the tutorial and storage spec (requires
+optional dependencies to be installed), run::
 
-Zarr currently supports Python 2.7 and Python 3.4-3.6, so the above command must
-succeed before code can be accepted into the main code base. Note that only the py36
-tox environment runs the doctests, i.e., doctests only need to succeed under Python 3.6.
+    $ python -m doctest -o NORMALIZE_WHITESPACE -o ELLIPSIS docs/tutorial.rst docs/spec/v2.rst
 
-All tests are automatically run via Travis (Linux) and AppVeyor (Windows) continuous
-integration services for every pull request. Tests must pass under both services before
-code can be accepted. Test coverage is also collected automatically via the Coveralls
-service, and total coverage over all builds must be 100% (although individual builds
-may be lower due to Python 2/3 or other differences).
+Note that some tests also require storage services to be running
+locally. To run the Azure Blob Service storage tests, run an Azure
+storage emulator (e.g., azurite) and set the environment variable
+``ZARR_TEST_ABS=1``. To run the Mongo DB storage tests, run a Mongo
+server locally and set the environment variable ``ZARR_TEST_MONGO=1``.
+To run the Redis storage tests, run a Redis server locally on port
+6379 and set the environment variable ``ZARR_TEST_REDIS=1``.
+
+All tests are automatically run via Travis (Linux) and AppVeyor
+(Windows) continuous integration services for every pull
+request. Tests must pass under both Travis and Appveyor before code
+can be accepted. Test coverage is also collected automatically via the
+Coveralls service, and total coverage over all builds must be 100%
+(although individual builds may be lower due to Python 2/3 or other
+differences).
 
 Code standards
 ~~~~~~~~~~~~~~
@@ -177,8 +186,6 @@ Conformance can be checked by running::
 
     $ flake8 --max-line-length=100 zarr
 
-This is automatically run when invoking ``tox -e py36``.
-
 Test coverage
 ~~~~~~~~~~~~~
 
@@ -195,10 +202,15 @@ request. Coveralls coverage must also be 100% before code can be accepted.
 Documentation
 ~~~~~~~~~~~~~
 
-Docstrings for user-facing classes and functions should follow the `numpydoc
-<https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt>`_ standard,
-including sections for Parameters and Examples. All examples should run and pass as doctests
-under Python 3.6 only.
+Docstrings for user-facing classes and functions should follow the
+`numpydoc
+<https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt>`_
+standard, including sections for Parameters and Examples. All examples
+should run and pass as doctests under Python 3.7. To run doctests,
+activate your development environment, install optional requirements,
+and run::
+
+    $ pytest -v --doctest-plus zarr
 
 Zarr uses Sphinx for documentation, hosted on readthedocs.org. Documentation is
 written in the RestructuredText markup language (.rst files) in the ``docs`` folder.
@@ -208,7 +220,7 @@ folder. Any new features or important usage information should be included in th
 tutorial (``docs/tutorial.rst``). Any changes should also be included in the release
 notes (``docs/release.rst``).
 
-The documentation can be built by running::
+The documentation can be built locally by running::
 
     $ tox -e docs
 
diff --git a/docs/release.rst b/docs/release.rst
index 8626ace746..84a6e0853d 100644
--- a/docs/release.rst
+++ b/docs/release.rst
@@ -6,11 +6,14 @@ Upcoming Release
 
 * Use uniform chunking for all dimensions when specifying ``chunks`` as an integer.
   Also adds support for specifying ``-1`` to chunk across an entire dimension.
-  By :user:`James Bourbeau <jrbourbeau>`; :issue:`456`
+  By :user:`James Bourbeau <jrbourbeau>`; :issue:`456`.
 
 * Rename ``DictStore`` to ``MemoryStore``.
-  By :user:`James Bourbeau <jrbourbeau>`; :issue:`455`
+  By :user:`James Bourbeau <jrbourbeau>`; :issue:`455`.
 
+* Upgrade dependencies in the test matrices and resolve a
+  compatibility issue with testing against the Azure Storage
+  Emulator. By :user:`alimanfoo`; :issue:`468`, :issue:`467`.
 
 .. _release_2.3.2:
 
@@ -21,19 +24,19 @@ Enhancements
 ~~~~~~~~~~~~
 
 * Use ``scandir`` in ``DirectoryStore``'s ``getsize`` method.
-  By :user:`John Kirkham <jakirkham>`; :issue:`431`
+  By :user:`John Kirkham <jakirkham>`; :issue:`431`.
 
 Bug fixes
 ~~~~~~~~~
 
 * Add and use utility functions to simplify reading and writing JSON.
-  By :user:`John Kirkham <jakirkham>`; :issue:`429`, :issue:`430`
+  By :user:`John Kirkham <jakirkham>`; :issue:`429`, :issue:`430`.
 
 * Fix ``collections``'s ``DeprecationWarning``\ s.
-  By :user:`John Kirkham <jakirkham>`; :issue:`432`
+  By :user:`John Kirkham <jakirkham>`; :issue:`432`.
 
 * Fix tests on big endian machines.
-  By :user:`Elliott Sales de Andrade <QuLogic>`; :issue:`427`
+  By :user:`Elliott Sales de Andrade <QuLogic>`; :issue:`427`.
 
 
 .. _release_2.3.1:
diff --git a/docs/tutorial.rst b/docs/tutorial.rst
index 09f6e4ae2d..b6f239d71d 100644
--- a/docs/tutorial.rst
+++ b/docs/tutorial.rst
@@ -806,10 +806,10 @@ The class is :class:`zarr.storage.ABSStore` (requires
  `azure-storage-blob <https://docs.microsoft.com/en-us/azure/storage/blobs/storage-quickstart-blobs-python>`_
 to be installed)::
 
-    >>> store = zarr.ABSStore(container='test', prefix='zarr-testing', blob_service_kwargs={'is_emulated': True})
-    >>> root = zarr.group(store=store, overwrite=True)
-    >>> z = root.zeros('foo/bar', shape=(1000, 1000), chunks=(100, 100), dtype='i4')
-    >>> z[:] = 42
+    >>> store = zarr.ABSStore(container='test', prefix='zarr-testing', blob_service_kwargs={'is_emulated': True})  # doctest: +SKIP
+    >>> root = zarr.group(store=store, overwrite=True)  # doctest: +SKIP
+    >>> z = root.zeros('foo/bar', shape=(1000, 1000), chunks=(100, 100), dtype='i4')  # doctest: +SKIP
+    >>> z[:] = 42  # doctest: +SKIP
 
 When using an actual storage account, provide ``account_name`` and
 ``account_key`` arguments to :class:`zarr.storage.ABSStore`, the
diff --git a/requirements.txt b/requirements.txt
deleted file mode 100644
index e035a2fc72..0000000000
--- a/requirements.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-asciitree
-fasteners
-numcodecs
-numpy
-pytest
-pyosreplace; python_version < '3.3' and sys.platform == 'win32'
diff --git a/requirements_dev.txt b/requirements_dev.txt
deleted file mode 100644
index 957edac387..0000000000
--- a/requirements_dev.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-asciitree==0.3.3
-fasteners==0.14.1
-numcodecs==0.6.2
-pyosreplace==0.1; python_version < '3.3' and sys.platform == 'win32'
diff --git a/requirements_dev_minimal.txt b/requirements_dev_minimal.txt
new file mode 100644
index 0000000000..7a89c04bd6
--- /dev/null
+++ b/requirements_dev_minimal.txt
@@ -0,0 +1,9 @@
+# library requirements
+asciitree==0.3.3
+fasteners==0.15
+numcodecs==0.6.3
+msgpack-python==0.5.6
+setuptools-scm==3.3.3
+# test requirements
+pytest==5.0.1; python_version > '3.0'
+pytest==4.6.5; python_version < '3.0'
diff --git a/requirements_dev_npy.txt b/requirements_dev_numpy.txt
similarity index 65%
rename from requirements_dev_npy.txt
rename to requirements_dev_numpy.txt
index 78b80223e2..1dd7939972 100644
--- a/requirements_dev_npy.txt
+++ b/requirements_dev_numpy.txt
@@ -1,4 +1,5 @@
 # Break this out into a separate file to allow testing against
 # different versions of numpy. This file should pin to the latest
 # numpy version.
-numpy==1.15.4
+numpy==1.17.0; python_version > '3.0'
+numpy==1.16.4; python_version < '3.0'
diff --git a/requirements_dev_optional.txt b/requirements_dev_optional.txt
index 2e4feddce0..3df1f1e3c0 100644
--- a/requirements_dev_optional.txt
+++ b/requirements_dev_optional.txt
@@ -1,5 +1,17 @@
-# These packages are currently not available on Windows.
-bsddb3==6.2.6
-lmdb==0.94
-redis==3.0.1
-pymongo==3.7.1
\ No newline at end of file
+# optional library requirements
+bsddb3==6.2.6; sys_platform != 'win32'
+lmdb==0.97; sys_platform != 'win32'
+# optional library requirements for services
+azure-storage-blob==2.0.1
+redis==3.3.6
+pymongo==3.8.0
+# optional test requirements
+tox==3.13.2
+coverage==4.5.4
+coveralls==1.8.2
+flake8==3.7.8
+pytest-cov==2.7.1
+pytest-doctestplus==0.3.0
+pytest-remotedata==0.3.2
+h5py==2.9.0
+s3fs==0.3.3; python_version > '3.0'
diff --git a/requirements_test.txt b/requirements_test.txt
deleted file mode 100644
index 1492a673c1..0000000000
--- a/requirements_test.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-coverage
-coveralls
-cython
-flake8
-h5py
-msgpack-python
-pytest
-pytest-cov
-s3fs
-setuptools-scm
-tox
-azure-storage-blob
diff --git a/tox.ini b/tox.ini
index 29303876a6..2a466b8731 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,9 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-# N.B., test different versions of numpy under py36 rather than py37
-# because wheels for npy113 not available for py37
-envlist = py27, py35, py36-npy{113,114,115}, py37, docs
+envlist = py27, py35, py36, py37-npy{115,116,latest}, docs
 
 [testenv]
 install_command = pip install --no-binary=numcodecs {opts} {packages}
@@ -15,35 +13,37 @@ setenv =
     # hooks for coverage exclusions based on Python major version
     py35,py36,py37: PY_MAJOR_VERSION = py3
     py27: PY_MAJOR_VERSION = py2
+passenv =
+    ZARR_TEST_ABS
+    ZARR_TEST_MONGO
+    ZARR_TEST_REDIS
 commands =
     # clear out any data files generated during tests
     python -c 'import glob; import shutil; import os; [(shutil.rmtree(d) if os.path.isdir(d) else os.remove(d) if os.path.isfile(d) else None) for d in glob.glob("./example*")]'
     # main unit test runner
-    # N.B., don't run npy113 or npy114 with coverage because it is run together npy115 on travis
-    py27,py35,py36-npy115: pytest -v --cov=zarr --cov-config=.coveragerc zarr
-    py36-npy113: pytest -v zarr
-    py36-npy114: pytest -v zarr
-    py37: pytest -v --cov=zarr --cov-config=.coveragerc --doctest-modules zarr
-    # generate a coverate report
-    py27,py35,py36-npy115,py37: coverage report -m
+    py27,py35,py36: pytest -v --cov=zarr --cov-config=.coveragerc zarr
+    # don't collect coverage when running older numpy versions
+    py37-{npy115,npy116}: pytest -v zarr
+    # collect coverage and run doctests under py37
+    py37-npylatest: pytest -v --cov=zarr --cov-config=.coveragerc --doctest-plus zarr --remote-data
+    # generate a coverage report
+    py27,py35,py36,py37-npylatest: coverage report -m
     # run doctests in the tutorial and spec
-    py37: python -m doctest -o NORMALIZE_WHITESPACE -o ELLIPSIS docs/tutorial.rst docs/spec/v2.rst
+    py37-npylatest: python -m doctest -o NORMALIZE_WHITESPACE -o ELLIPSIS docs/tutorial.rst docs/spec/v2.rst
     # pep8 checks
-    py37: flake8 zarr
+    py37-npylatest: flake8 zarr
     # print environment for debugging
     pip freeze
 deps =
     py27: backports.lzma
-    py36-npy113: numpy==1.13.3
-    py36-npy114: numpy==1.14.6
-    py27,py35,py36-npy115,py37: -rrequirements_dev_npy.txt
-    -rrequirements_test.txt
-    -rrequirements_dev.txt
-    # linux only
+    py37-npy115: numpy==1.15.4
+    py37-npy116: numpy==1.16.4
+    py27,py35,py36,py37-npylatest: -rrequirements_dev_numpy.txt
+    -rrequirements_dev_minimal.txt
     -rrequirements_dev_optional.txt
 
 [testenv:docs]
-basepython = python2.7
+basepython = python3.6
 changedir = docs
 deps =
     -rrequirements_rtfd.txt
diff --git a/zarr/indexing.py b/zarr/indexing.py
index 0cd116bc37..988489e0bb 100644
--- a/zarr/indexing.py
+++ b/zarr/indexing.py
@@ -693,7 +693,11 @@ def __init__(self, selection, array):
         self.chunk_rixs = np.nonzero(self.chunk_nitems)[0]
 
         # unravel chunk indices
-        self.chunk_mixs = np.unravel_index(self.chunk_rixs, dims=array._cdata_shape)
+        if tuple(map(int, np.__version__.split('.')[:2])) < (1, 16):
+            self.chunk_mixs = np.unravel_index(self.chunk_rixs, dims=array._cdata_shape)
+        else:
+            # deal with change dims->shape in arguments as of numpy 1.16
+            self.chunk_mixs = np.unravel_index(self.chunk_rixs, shape=array._cdata_shape)
 
     def __iter__(self):
 
diff --git a/zarr/storage.py b/zarr/storage.py
index 9e608da0d2..03ebdefeac 100644
--- a/zarr/storage.py
+++ b/zarr/storage.py
@@ -44,6 +44,14 @@
                          err_fspath_exists_notdir, err_read_only, MetadataError)
 
 
+__doctest_requires__ = {
+    ('RedisStore', 'RedisStore.*'): ['redis'],
+    ('MongoDBStore', 'MongoDBStore.*'): ['pymongo'],
+    ('ABSStore', 'ABSStore.*'): ['azure.storage.blob'],
+    ('LRUStoreCache', 'LRUStoreCache.*'): ['s3fs'],
+}
+
+
 array_meta_key = '.zarray'
 group_meta_key = '.zgroup'
 attrs_key = '.zattrs'
@@ -1099,8 +1107,10 @@ class also supports the context manager protocol, which ensures the ``close()``
 
         >>> store = zarr.ZipStore('data/example.zip', mode='w')
         >>> z = zarr.zeros(100, chunks=10, store=store)
-        >>> z[...] = 42  # first write OK
-        >>> z[...] = 42  # second write generates warnings
+        >>> # first write OK
+        ... z[...] = 42
+        >>> # second write generates warnings
+        ... z[...] = 42  # doctest: +SKIP
         >>> store.close()
 
     This can also happen in a more subtle situation, where data are written only
@@ -1110,7 +1120,8 @@ class also supports the context manager protocol, which ensures the ``close()``
         >>> store = zarr.ZipStore('data/example.zip', mode='w')
         >>> z = zarr.zeros(100, chunks=10, store=store)
         >>> z[5:15] = 42
-        >>> z[15:25] = 42  # write overlaps chunk previously written, generates warnings
+        >>> # write overlaps chunk previously written, generates warnings
+        ... z[15:25] = 42  # doctest: +SKIP
 
     To avoid creating duplicate entries, only write data once, and align writes
     with chunk boundaries. This alignment is done automatically if you call
@@ -1729,8 +1740,8 @@ class LRUStoreCache(MutableMapping):
         >>> s3 = s3fs.S3FileSystem(anon=True, client_kwargs=dict(region_name='eu-west-2'))
         >>> store = s3fs.S3Map(root='zarr-demo/store', s3=s3, check=False)
         >>> cache = zarr.LRUStoreCache(store, max_size=2**28)
-        >>> root = zarr.group(store=cache)
-        >>> z = root['foo/bar/baz']
+        >>> root = zarr.group(store=cache)  # doctest: +REMOTE_DATA
+        >>> z = root['foo/bar/baz']  # doctest: +REMOTE_DATA
         >>> from timeit import timeit
         >>> # first data access is relatively slow, retrieved from store
         ... timeit('print(z[:].tostring())', number=1, globals=globals())  # doctest: +SKIP
@@ -2257,25 +2268,6 @@ class MongoDBStore(MutableMapping):
     **kwargs
         Keyword arguments passed through to the `pymongo.MongoClient` function.
 
-    Examples
-    --------
-    Store a single array::
-
-        >>> import zarr
-        >>> store = zarr.MongoDBStore('localhost')
-        >>> z = zarr.zeros((10, 10), chunks=(5, 5), store=store, overwrite=True)
-        >>> z[...] = 42
-        >>> store.close()
-
-    Store a group::
-
-        >>> store = zarr.MongoDBStore('localhost')
-        >>> root = zarr.group(store=store, overwrite=True)
-        >>> foo = root.create_group('foo')
-        >>> bar = foo.zeros('bar', shape=(10, 10), chunks=(5, 5))
-        >>> bar[...] = 42
-        >>> store.close()
-
     Notes
     -----
     The maximum chunksize in MongoDB documents is 16 MB.
@@ -2354,23 +2346,6 @@ class RedisStore(MutableMapping):
     **kwargs
         Keyword arguments passed through to the `redis.Redis` function.
 
-    Examples
-    --------
-    Store a single array::
-
-        >>> import zarr
-        >>> store = zarr.RedisStore(port=6379)
-        >>> z = zarr.zeros((10, 10), chunks=(5, 5), store=store, overwrite=True)
-        >>> z[...] = 42
-
-    Store a group::
-
-        >>> store = zarr.RedisStore(port=6379)
-        >>> root = zarr.group(store=store, overwrite=True)
-        >>> foo = root.create_group('foo')
-        >>> bar = foo.zeros('bar', shape=(10, 10), chunks=(5, 5))
-        >>> bar[...] = 42
-
     """
     def __init__(self, prefix='zarr', **kwargs):
         import redis
diff --git a/zarr/tests/test_core.py b/zarr/tests/test_core.py
index 7fb905198f..43daca9f03 100644
--- a/zarr/tests/test_core.py
+++ b/zarr/tests/test_core.py
@@ -34,6 +34,11 @@
 from numcodecs.tests.common import greetings
 
 
+# also check for environment variables indicating whether tests requiring
+# services should be run
+ZARR_TEST_ABS = os.environ.get('ZARR_TEST_ABS', '0')
+
+
 # needed for PY2/PY3 consistent behaviour
 if PY2:  # pragma: py3 no cover
     warnings.resetwarnings()
@@ -1412,8 +1417,9 @@ def test_nbytes_stored(self):
         assert expect_nbytes_stored == z.nbytes_stored
 
 
-@pytest.mark.skipif(asb is None,
-                    reason="azure-blob-storage could not be imported")
+@pytest.mark.skipif(asb is None or ZARR_TEST_ABS == '0',
+                    reason="azure-blob-storage could not be imported or tests not"
+                           "enabled via environment variable")
 class TestArrayWithABSStore(TestArray):
 
     @staticmethod
diff --git a/zarr/tests/test_hierarchy.py b/zarr/tests/test_hierarchy.py
index 30bcd484cf..546e2ab93f 100644
--- a/zarr/tests/test_hierarchy.py
+++ b/zarr/tests/test_hierarchy.py
@@ -34,6 +34,11 @@
 from numcodecs import Zlib
 
 
+# also check for environment variables indicating whether tests requiring
+# services should be run
+ZARR_TEST_ABS = os.environ.get('ZARR_TEST_ABS', '0')
+
+
 # needed for PY2/PY3 consistent behaviour
 if PY2:  # pragma: py3 no cover
     warnings.resetwarnings()
@@ -869,8 +874,9 @@ def create_store():
         return store, None
 
 
-@pytest.mark.skipif(asb is None,
-                    reason="azure-blob-storage could not be imported")
+@pytest.mark.skipif(asb is None or ZARR_TEST_ABS == '0',
+                    reason="azure-blob-storage could not be imported or tests not enabled"
+                           "via environment variable")
 class TestGroupWithABSStore(TestGroup):
 
     @staticmethod
diff --git a/zarr/tests/test_storage.py b/zarr/tests/test_storage.py
index b21341c464..a713acaf8a 100644
--- a/zarr/tests/test_storage.py
+++ b/zarr/tests/test_storage.py
@@ -16,11 +16,25 @@
 from numpy.testing import assert_array_equal, assert_array_almost_equal
 import pytest
 
+try:
+    import sqlite3
+except ImportError:  # pragma: no cover
+    sqlite3 = None
+
 try:
     import azure.storage.blob as asb
 except ImportError:  # pragma: no cover
     asb = None
 
+try:
+    import pymongo
+except ImportError:  # pragma: no cover
+    pymongo = None
+
+try:
+    import redis
+except ImportError:  # pragma: no cover
+    redis = None
 
 from zarr.storage import (init_array, array_meta_key, attrs_key, DictStore, MemoryStore,
                           DirectoryStore, ZipStore, init_group, group_meta_key,
@@ -43,6 +57,13 @@
     LZMA = None
 
 
+# also check for environment variables indicating whether tests requiring
+# services should be run
+ZARR_TEST_ABS = os.environ.get('ZARR_TEST_ABS', '0')
+ZARR_TEST_MONGO = os.environ.get('ZARR_TEST_MONGO', '0')
+ZARR_TEST_REDIS = os.environ.get('ZARR_TEST_REDIS', '0')
+
+
 @contextmanager
 def does_not_raise():
     yield
@@ -984,7 +1005,7 @@ def create_store(self):
     gdbm = None
 
 
-@unittest.skipIf(gdbm is None, 'gdbm is not installed')
+@unittest.skipIf(gdbm is None, reason='gdbm is not installed')
 class TestDBMStoreGnu(TestDBMStore):
 
     def create_store(self):
@@ -1000,7 +1021,7 @@ def create_store(self):
     except ImportError:  # pragma: no cover
         ndbm = None
 
-    @unittest.skipIf(ndbm is None, 'ndbm is not installed')
+    @unittest.skipIf(ndbm is None, reason='ndbm is not installed')
     class TestDBMStoreNDBM(TestDBMStore):
 
         def create_store(self):
@@ -1016,7 +1037,7 @@ def create_store(self):
     bsddb3 = None
 
 
-@unittest.skipIf(bsddb3 is None, 'bsddb3 is not installed')
+@unittest.skipIf(bsddb3 is None, reason='bsddb3 is not installed')
 class TestDBMStoreBerkeleyDB(TestDBMStore):
 
     def create_store(self):
@@ -1032,7 +1053,7 @@ def create_store(self):
     lmdb = None
 
 
-@unittest.skipIf(lmdb is None, 'lmdb is not installed')
+@unittest.skipIf(lmdb is None, reason='lmdb is not installed')
 class TestLMDBStore(StoreTests, unittest.TestCase):
 
     def create_store(self):
@@ -1054,36 +1075,7 @@ def test_context_manager(self):
             assert 2 == len(store)
 
 
-try:
-    import sqlite3
-except ImportError:  # pragma: no cover
-    sqlite3 = None
-
-try:
-    import pymongo
-    from pymongo.errors import ConnectionFailure, ServerSelectionTimeoutError
-    try:
-        client = pymongo.MongoClient(host='127.0.0.1',
-                                     serverSelectionTimeoutMS=1e3)
-        client.server_info()
-    except (ConnectionFailure, ServerSelectionTimeoutError):  # pragma: no cover
-        pymongo = None
-except ImportError:  # pragma: no cover
-    pymongo = None
-
-try:
-    import redis
-    from redis import ConnectionError
-    try:
-        rs = redis.Redis("localhost", port=6379)
-        rs.ping()
-    except ConnectionError:  # pragma: no cover
-        redis = None
-except ImportError:  # pragma: no cover
-    redis = None
-
-
-@unittest.skipIf(sqlite3 is None, 'python built without sqlite')
+@unittest.skipIf(sqlite3 is None, reason='python built without sqlite')
 class TestSQLiteStore(StoreTests, unittest.TestCase):
 
     def create_store(self):
@@ -1093,7 +1085,7 @@ def create_store(self):
         return store
 
 
-@unittest.skipIf(sqlite3 is None, 'python built without sqlite')
+@unittest.skipIf(sqlite3 is None, reason='python built without sqlite')
 class TestSQLiteStoreInMemory(TestSQLiteStore, unittest.TestCase):
 
     def create_store(self):
@@ -1112,7 +1104,9 @@ def test_pickle(self):
             pickle.dumps(store)
 
 
-@unittest.skipIf(pymongo is None, 'test requires pymongo')
+@unittest.skipIf(pymongo is None or ZARR_TEST_MONGO == '0',
+                 reason='pymongo client library not installed or tests not enabled'
+                        'via environment variable')
 class TestMongoDBStore(StoreTests, unittest.TestCase):
 
     def create_store(self):
@@ -1123,7 +1117,9 @@ def create_store(self):
         return store
 
 
-@unittest.skipIf(redis is None, 'test requires redis')
+@unittest.skipIf(redis is None or ZARR_TEST_REDIS == '0',
+                 reason='redis client library not installed or tests not enabled'
+                        'via environment variable')
 class TestRedisStore(StoreTests, unittest.TestCase):
 
     def create_store(self):
@@ -1529,8 +1525,9 @@ def test_format_compatibility():
                 assert compressor.get_config() == z.compressor.get_config()
 
 
-@pytest.mark.skipif(asb is None,
-                    reason="azure-blob-storage could not be imported")
+@pytest.mark.skipif(asb is None or ZARR_TEST_ABS == '0',
+                    reason='azure blob storage client library not available or tests '
+                           'not enabled via environment variable')
 class TestABSStore(StoreTests, unittest.TestCase):
 
     def create_store(self):