diff --git a/.travis.yml b/.travis.yml
index ca33852f..f64b1a34 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,11 +20,3 @@ jobs:
           fi
           cardboardlinter --refspec $TRAVIS_BRANCH -n auto;
         fi
-    - name: python unit tests
-      install:
-        - pip install --upgrade -r requirements_tests.txt;
-          pip install --upgrade .
-      script:
-        - if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then
-            python -m unittest;
-          fi
diff --git a/taskcluster/tc-train-unittests.sh b/taskcluster/tc-train-unittests.sh
new file mode 100644
index 00000000..4be52e90
--- /dev/null
+++ b/taskcluster/tc-train-unittests.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -xe
+
+source $(dirname "$0")/tc-tests-utils.sh
+
+extract_python_versions "$1" "pyver" "pyver_pkg" "py_unicode_type" "pyconf" "pyalias"
+
+mkdir -p ${TASKCLUSTER_ARTIFACTS} || true
+
+virtualenv_activate "${pyalias}" "deepspeech"
+
+set -o pipefail
+pip install --upgrade pip==19.3.1 setuptools==45.0.0 wheel==0.33.6 | cat
+pushd ${HOME}/DeepSpeech/ds
+    pip install --upgrade . | cat
+    python -m unittest
+popd
+set +o pipefail
diff --git a/taskcluster/test-training-unittests_8k-linux-amd64-py35m-opt.yml b/taskcluster/test-training-unittests_8k-linux-amd64-py35m-opt.yml
new file mode 100644
index 00000000..d33ad21d
--- /dev/null
+++ b/taskcluster/test-training-unittests_8k-linux-amd64-py35m-opt.yml
@@ -0,0 +1,12 @@
+build:
+    template_file: test-linux-opt-base.tyml
+    dependencies:
+      - "linux-amd64-ctc-opt"
+    system_setup:
+      >
+        apt-get -qq update && apt-get -qq -y install ${training.packages_trusty.apt}
+    args:
+      tests_cmdline: "${system.homedir.linux}/DeepSpeech/ds/taskcluster/tc-train-unittests.sh 3.5.8:m"
+    metadata:
+      name: "DeepSpeech on Linux AMD64 CPU training unittests using Python 3.5"
+      description: "Training unittests DeepSpeech LDC93S1 model for Linux/AMD64 using Python 3.5, for CPU only, and optimized version"
diff --git a/taskcluster/test-training-unittests_8k-linux-amd64-py36m-opt.yml b/taskcluster/test-training-unittests_8k-linux-amd64-py36m-opt.yml
new file mode 100644
index 00000000..195ddfe9
--- /dev/null
+++ b/taskcluster/test-training-unittests_8k-linux-amd64-py36m-opt.yml
@@ -0,0 +1,13 @@
+build:
+    template_file: test-linux-opt-base.tyml
+    dependencies:
+      - "linux-amd64-ctc-opt"
+    system_setup:
+      >
+        apt-get -qq update && apt-get -qq -y install ${training.packages_trusty.apt}
+    args:
+      tests_cmdline: "${system.homedir.linux}/DeepSpeech/ds/taskcluster/tc-train-unittests.sh 3.6.10:m"
+    metadata:
+      name: "DeepSpeech on Linux AMD64 CPU training unittests using Python 3.6"
+      description: "Training unittests DeepSpeech LDC93S1 model for Linux/AMD64 using Python 3.6, for CPU only, and optimized version"
+ 
\ No newline at end of file
diff --git a/taskcluster/test-training-unittests_8k-linux-amd64-py37m-opt.yml b/taskcluster/test-training-unittests_8k-linux-amd64-py37m-opt.yml
new file mode 100644
index 00000000..1f9aabc3
--- /dev/null
+++ b/taskcluster/test-training-unittests_8k-linux-amd64-py37m-opt.yml
@@ -0,0 +1,12 @@
+build:
+    template_file: test-linux-opt-base.tyml
+    dependencies:
+      - "linux-amd64-ctc-opt"
+    system_setup:
+      >
+        apt-get -qq update && apt-get -qq -y install ${training.packages_trusty.apt}
+    args:
+      tests_cmdline: "${system.homedir.linux}/DeepSpeech/ds/taskcluster/tc-train-unittests.sh 3.7.6:m"
+    metadata:
+      name: "DeepSpeech on Linux AMD64 CPU training unittests using Python 3.7"
+      description: "Training unittests DeepSpeech LDC93S1 model for Linux/AMD64 using Python 3.7, for CPU only, and optimized version"
diff --git a/training/deepspeech_training/util/importers.py b/training/deepspeech_training/util/importers.py
index 4868e4a3..a4c3c326 100644
--- a/training/deepspeech_training/util/importers.py
+++ b/training/deepspeech_training/util/importers.py
@@ -42,15 +42,17 @@ def get_validate_label(args):
     :return: The user-supplied validate_label function
     :type: function
     """
+    # Python 3.5 does not support passing a pathlib.Path to os.path.* methods
     if 'validate_label_locale' not in args or (args.validate_label_locale is None):
         print('WARNING: No --validate_label_locale specified, your might end with inconsistent dataset.')
         return validate_label_eng
-    if not os.path.exists(os.path.abspath(args.validate_label_locale)):
+    validate_label_locale = str(args.validate_label_locale)
+    if not os.path.exists(os.path.abspath(validate_label_locale)):
         print('ERROR: Inexistent --validate_label_locale specified. Please check.')
         return None
-    module_dir = os.path.abspath(os.path.dirname(args.validate_label_locale))
+    module_dir = os.path.abspath(os.path.dirname(validate_label_locale))
     sys.path.insert(1, module_dir)
-    fname = os.path.basename(args.validate_label_locale).replace('.py', '')
+    fname = os.path.basename(validate_label_locale).replace('.py', '')
     locale_module = importlib.import_module(fname, package=None)
     return locale_module.validate_label