Add unittests

tools/ci/decision.py

diff --git a/tools/ci/decision.py b/tools/ci/decision.py
index 18d0df4..8a78593 100644
--- a/tools/ci/decision.py
+++ b/tools/ci/decision.py
@@ -109,6 +109,16 @@
 
     cmd_args["options_str"] = "\n".join("  %s" % item for item in options_args)
 
+    install_str = "";
+    install_packages = task.get("install")
+    if install_packages:
+        install_items = ["apt update -qqy"]
+        install_items.extend("apt install -qqy %s" % item
+                             for item in install_packages)
+        install_str = "\n".join("sudo %s;" % item for item in install_items)
+
+    cmd_args["install_cmd"] = install_str
+
     return ["/bin/bash",
             "--login",
             "-c",
@@ -116,6 +126,7 @@
 ~/start.sh
   %(repo_url)s
   %(fetch_rev)s;
+%(install_str)s
 cd web-platform-tests;
 ./tools/ci/run_tc.py
   %(options_str)s

tools/ci/tasks/test.yml

diff --git a/tools/ci/tasks/test.yml b/tools/ci/tasks/test.yml
index d497f35..198b2e5 100644
--- a/tools/ci/tasks/test.yml
+++ b/tools/ci/tasks/test.yml
@@ -218,3 +218,22 @@
           - update_built
       command: "tools/ci/ci_built_diff.sh"
 
+  - tools/unittests (Python 2):
+      description: >-
+        Unit tests for tools running under Python 2.7, excluding wptrunner
+      command: tools/ci/ci_tools_unittest.sh
+      env:
+        - TOXENV=py27;
+        - HYPOTHESIS_PROFILE=ci;
+        - PY_COLORS=0;
+
+  - tools/unittests (Python 3):
+      description: >-
+        Unit tests for tools running under Python 3, excluding wptrunner
+      command: tools/ci/ci_tools_unittest.sh
+      env:
+        - TOXENV=py36;
+        - HYPOTHESIS_PROFILE=ci;
+        - PY_COLORS=0;
+      install:
+        - python3-pip