diff --git a/keyosk/database/__init__.py b/keyosk/database/__init__.py
index 5e882b2..c648750 100644
--- a/keyosk/database/__init__.py
+++ b/keyosk/database/__init__.py
@@ -60,8 +60,10 @@ def initialize(conf: config.KeyoskConfig):
     if conf.storage.backend == datatypes.StorageBackend.SQLITE:
         logger.debug("Using SQLite database backend")
         logger.debug(f"Applying SQLite pragmas: {conf.storage.sqlite.pragmas}")
+        # Explicit cast-to-string on the path is to support py3.6: sqlite driver
+        # requires a string, vs 3.7+ requires a string-like object
         database = peewee.SqliteDatabase(
-            conf.storage.sqlite.path, pragmas=conf.storage.sqlite.pragmas
+            str(conf.storage.sqlite.path), pragmas=conf.storage.sqlite.pragmas
         )
 
     elif conf.storage.backend == datatypes.StorageBackend.MARIA:
diff --git a/poetry.lock b/poetry.lock
index 5d55643..aa7ac61 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -174,6 +174,17 @@ optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 version = "0.4.3"
 
+[[package]]
+category = "dev"
+description = "Code coverage measurement for Python"
+name = "coverage"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, <4"
+version = "5.0.3"
+
+[package.extras]
+toml = ["toml"]
+
 [[package]]
 category = "main"
 description = "A backport of the dataclasses module for Python 3.6"
@@ -666,6 +677,21 @@ version = ">=0.12"
 checkqa-mypy = ["mypy (v0.761)"]
 testing = ["argcomplete", "hypothesis (>=3.56)", "mock", "nose", "requests", "xmlschema"]
 
+[[package]]
+category = "dev"
+description = "Pytest plugin for measuring coverage."
+name = "pytest-cov"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+version = "2.8.1"
+
+[package.dependencies]
+coverage = ">=4.4"
+pytest = ">=3.6"
+
+[package.extras]
+testing = ["fields", "hunter", "process-tests (2.0.2)", "six", "virtualenv"]
+
 [[package]]
 category = "dev"
 description = "World timezone definitions, modern and historical"
@@ -1002,7 +1028,7 @@ docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
 testing = ["jaraco.itertools", "func-timeout"]
 
 [metadata]
-content-hash = "ee3f3004fd07138b487c922bb190c151aafa692c72a6d8f3a736aec017e53381"
+content-hash = "104a9f1ae051efabd1282bed7ad70f349fadbc625dde4f977fa67f3efa2cc76b"
 python-versions = "^3.6"
 
 [metadata.files]
@@ -1074,6 +1100,39 @@ colorama = [
     {file = "colorama-0.4.3-py2.py3-none-any.whl", hash = "sha256:7d73d2a99753107a36ac6b455ee49046802e59d9d076ef8e47b61499fa29afff"},
     {file = "colorama-0.4.3.tar.gz", hash = "sha256:e96da0d330793e2cb9485e9ddfd918d456036c7149416295932478192f4436a1"},
 ]
+coverage = [
+    {file = "coverage-5.0.3-cp27-cp27m-macosx_10_12_x86_64.whl", hash = "sha256:cc1109f54a14d940b8512ee9f1c3975c181bbb200306c6d8b87d93376538782f"},
+    {file = "coverage-5.0.3-cp27-cp27m-macosx_10_13_intel.whl", hash = "sha256:be18f4ae5a9e46edae3f329de2191747966a34a3d93046dbdf897319923923bc"},
+    {file = "coverage-5.0.3-cp27-cp27m-manylinux1_i686.whl", hash = "sha256:3230d1003eec018ad4a472d254991e34241e0bbd513e97a29727c7c2f637bd2a"},
+    {file = "coverage-5.0.3-cp27-cp27m-manylinux1_x86_64.whl", hash = "sha256:e69215621707119c6baf99bda014a45b999d37602cb7043d943c76a59b05bf52"},
+    {file = "coverage-5.0.3-cp27-cp27m-win32.whl", hash = "sha256:1daa3eceed220f9fdb80d5ff950dd95112cd27f70d004c7918ca6dfc6c47054c"},
+    {file = "coverage-5.0.3-cp27-cp27m-win_amd64.whl", hash = "sha256:51bc7710b13a2ae0c726f69756cf7ffd4362f4ac36546e243136187cfcc8aa73"},
+    {file = "coverage-5.0.3-cp27-cp27mu-manylinux1_i686.whl", hash = "sha256:9bea19ac2f08672636350f203db89382121c9c2ade85d945953ef3c8cf9d2a68"},
+    {file = "coverage-5.0.3-cp27-cp27mu-manylinux1_x86_64.whl", hash = "sha256:5012d3b8d5a500834783689a5d2292fe06ec75dc86ee1ccdad04b6f5bf231691"},
+    {file = "coverage-5.0.3-cp35-cp35m-macosx_10_12_x86_64.whl", hash = "sha256:d513cc3db248e566e07a0da99c230aca3556d9b09ed02f420664e2da97eac301"},
+    {file = "coverage-5.0.3-cp35-cp35m-manylinux1_i686.whl", hash = "sha256:3dbb72eaeea5763676a1a1efd9b427a048c97c39ed92e13336e726117d0b72bf"},
+    {file = "coverage-5.0.3-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:15cf13a6896048d6d947bf7d222f36e4809ab926894beb748fc9caa14605d9c3"},
+    {file = "coverage-5.0.3-cp35-cp35m-win32.whl", hash = "sha256:fca1669d464f0c9831fd10be2eef6b86f5ebd76c724d1e0706ebdff86bb4adf0"},
+    {file = "coverage-5.0.3-cp35-cp35m-win_amd64.whl", hash = "sha256:1e44a022500d944d42f94df76727ba3fc0a5c0b672c358b61067abb88caee7a0"},
+    {file = "coverage-5.0.3-cp36-cp36m-macosx_10_13_x86_64.whl", hash = "sha256:b26aaf69713e5674efbde4d728fb7124e429c9466aeaf5f4a7e9e699b12c9fe2"},
+    {file = "coverage-5.0.3-cp36-cp36m-manylinux1_i686.whl", hash = "sha256:722e4557c8039aad9592c6a4213db75da08c2cd9945320220634f637251c3894"},
+    {file = "coverage-5.0.3-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:7afad9835e7a651d3551eab18cbc0fdb888f0a6136169fbef0662d9cdc9987cf"},
+    {file = "coverage-5.0.3-cp36-cp36m-win32.whl", hash = "sha256:25dbf1110d70bab68a74b4b9d74f30e99b177cde3388e07cc7272f2168bd1477"},
+    {file = "coverage-5.0.3-cp36-cp36m-win_amd64.whl", hash = "sha256:c312e57847db2526bc92b9bfa78266bfbaabac3fdcd751df4d062cd4c23e46dc"},
+    {file = "coverage-5.0.3-cp37-cp37m-macosx_10_13_x86_64.whl", hash = "sha256:a8b8ac7876bc3598e43e2603f772d2353d9931709345ad6c1149009fd1bc81b8"},
+    {file = "coverage-5.0.3-cp37-cp37m-manylinux1_i686.whl", hash = "sha256:527b4f316e6bf7755082a783726da20671a0cc388b786a64417780b90565b987"},
+    {file = "coverage-5.0.3-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:d649dc0bcace6fcdb446ae02b98798a856593b19b637c1b9af8edadf2b150bea"},
+    {file = "coverage-5.0.3-cp37-cp37m-win32.whl", hash = "sha256:cd60f507c125ac0ad83f05803063bed27e50fa903b9c2cfee3f8a6867ca600fc"},
+    {file = "coverage-5.0.3-cp37-cp37m-win_amd64.whl", hash = "sha256:c60097190fe9dc2b329a0eb03393e2e0829156a589bd732e70794c0dd804258e"},
+    {file = "coverage-5.0.3-cp38-cp38-macosx_10_13_x86_64.whl", hash = "sha256:d7008a6796095a79544f4da1ee49418901961c97ca9e9d44904205ff7d6aa8cb"},
+    {file = "coverage-5.0.3-cp38-cp38-manylinux1_i686.whl", hash = "sha256:ea9525e0fef2de9208250d6c5aeeee0138921057cd67fcef90fbed49c4d62d37"},
+    {file = "coverage-5.0.3-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:c62a2143e1313944bf4a5ab34fd3b4be15367a02e9478b0ce800cb510e3bbb9d"},
+    {file = "coverage-5.0.3-cp38-cp38m-win32.whl", hash = "sha256:b0840b45187699affd4c6588286d429cd79a99d509fe3de0f209594669bb0954"},
+    {file = "coverage-5.0.3-cp38-cp38m-win_amd64.whl", hash = "sha256:76e2057e8ffba5472fd28a3a010431fd9e928885ff480cb278877c6e9943cc2e"},
+    {file = "coverage-5.0.3-cp39-cp39m-win32.whl", hash = "sha256:b63dd43f455ba878e5e9f80ba4f748c0a2156dde6e0e6e690310e24d6e8caf40"},
+    {file = "coverage-5.0.3-cp39-cp39m-win_amd64.whl", hash = "sha256:da93027835164b8223e8e5af2cf902a4c80ed93cb0909417234f4a9df3bcd9af"},
+    {file = "coverage-5.0.3.tar.gz", hash = "sha256:77afca04240c40450c331fa796b3eab6f1e15c5ecf8bf2b8bee9706cd5452fef"},
+]
 dataclasses = [
     {file = "dataclasses-0.7-py3-none-any.whl", hash = "sha256:3459118f7ede7c8bea0fe795bff7c6c2ce287d01dd226202f7c9ebc0610a7836"},
     {file = "dataclasses-0.7.tar.gz", hash = "sha256:494a6dcae3b8bcf80848eea2ef64c0cc5cd307ffc263e17cdf42f3e5420808e6"},
@@ -1300,6 +1359,10 @@ pytest = [
     {file = "pytest-5.3.5-py3-none-any.whl", hash = "sha256:ff615c761e25eb25df19edddc0b970302d2a9091fbce0e7213298d85fb61fef6"},
     {file = "pytest-5.3.5.tar.gz", hash = "sha256:0d5fe9189a148acc3c3eb2ac8e1ac0742cb7618c084f3d228baaec0c254b318d"},
 ]
+pytest-cov = [
+    {file = "pytest-cov-2.8.1.tar.gz", hash = "sha256:cc6742d8bac45070217169f5f72ceee1e0e55b0221f54bcf24845972d3a47f2b"},
+    {file = "pytest_cov-2.8.1-py2.py3-none-any.whl", hash = "sha256:cdbdef4f870408ebdbfeb44e63e07eb18bb4619fae852f6e760645fa36172626"},
+]
 pytz = [
     {file = "pytz-2019.3-py2.py3-none-any.whl", hash = "sha256:1c557d7d0e871de1f5ccd5833f60fb2550652da6be2693c1e02300743d21500d"},
     {file = "pytz-2019.3.tar.gz", hash = "sha256:b02c06db6cf09c12dd25137e563b31700d3b80fcc4ad23abb7a315f2789819be"},
diff --git a/pyproject.toml b/pyproject.toml
index c8c2fc7..2f5023b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,6 +29,7 @@ pytest = "^5.3.5"
 black = {version = "^19.10b0", allow-prereleases = true}
 pylint = "2.3.1"
 astroid = "2.2.5"
+pytest-cov = "^2.8.1"
 
 [build-system]
 requires = ["poetry>=1.0.0"]
diff --git a/tox.ini b/tox.ini
index 6ea8145..53669fd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,18 +5,19 @@ isolated_build = true
 [testenv]
 description = Run the unit tests (pytest)
 deps =
-    pytest
-    pytest-cov
-    toml
-    passlib
-    marshmallow
+    marshmallow == 3.5.0
+    passlib == 1.7.2
+    peewee == 3.13.1
+    pytest == 5.3.5
+    pytest-cov == 2.8.1
+    toml == 0.10.0
 commands =
     pytest --cov={envsitepackagesdir}/keyosk --cov-config .coveragerc tests/ --cov-report term-missing
 
 [testenv:lint]
 description = Check code formatting against black and pylint
 deps =
-    pre-commit
+    pre-commit == 2.1.0
     pylint == 2.3.1
     astroid == 2.2.5
 commands =
@@ -26,22 +27,22 @@ commands =
 [testenv:typing]
 description = Check type annotations with mypy
 deps =
-    mypy
+    mypy == 0.761
 commands =
     mypy keyosk --ignore-missing-imports --no-strict-optional
 
 [testenv:security]
 description = Check security vulnerabilities (bandit)
 deps =
-    bandit
+    bandit == 1.6.2
 commands =
     bandit --recursive keyosk
 
 [testenv:docs]
 description = Build documentation to check RST syntax (sphinx)
 deps =
-    sphinx >= 1.7.5, < 2.0
-    sphinx-autodoc-typehints >= 1.3.0, < 2.0
+    sphinx == 2.4.2
+    sphinx-autodoc-typehints == 1.10.3
 whitelist_externals =
     rm
 commands =