diff --git a/Pipfile b/Pipfile
index f772a51a..eb946fb9 100644
--- a/Pipfile
+++ b/Pipfile
@@ -19,6 +19,7 @@ ipython = "*"
 ipdb = "*"
 pylint = "*"
 black = "*"
+pytest-watch = "*"
 
 [requires]
 python_version = "3.6"
diff --git a/Pipfile.lock b/Pipfile.lock
index 2cf47dcc..2fadae1e 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "53a2048f5dc853a0ac2d565164c23dcdb2df802e055c1530864bfc8390af3c3e"
+            "sha256": "3bea02ccdb0e3877f2595d7fb405408114ec8947e0484d5b4aaf14a4c8ff78b2"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -119,6 +119,13 @@
             "markers": "sys_platform == 'darwin'",
             "version": "==0.1.0"
         },
+        "argh": {
+            "hashes": [
+                "sha256:a9b3aaa1904eeb78e32394cd46c6f37ac0fb4af6dc488daa58971bdc7d7fcaf3",
+                "sha256:e9535b8c84dc9571a48999094fda7f33e63c3f1b74f3e5f3ac0105a58405bb65"
+            ],
+            "version": "==0.26.2"
+        },
         "astroid": {
             "hashes": [
                 "sha256:a8d8c7fe34e34e868426b9bafce852c355a3951eef60bc831b2ed541558f8d37",
@@ -170,6 +177,13 @@
             ],
             "version": "==6.7"
         },
+        "colorama": {
+            "hashes": [
+                "sha256:463f8483208e921368c9f306094eb6f725c6ca42b0f97e313cb5d5512459feda",
+                "sha256:48eb22f4f8461b1df5734a074b57042430fb06e1d61bd1e11b078c0fe6d7a1f1"
+            ],
+            "version": "==0.3.9"
+        },
         "decorator": {
             "hashes": [
                 "sha256:2c51dff8ef3c447388fe5e4453d24a2bf128d3a4c32af3fabef1f01c6851ab82",
@@ -177,6 +191,12 @@
             ],
             "version": "==4.3.0"
         },
+        "docopt": {
+            "hashes": [
+                "sha256:49b3a825280bd66b3aa83585ef59c4a8c82f2c8a522dbe754a8bc8d08c85c491"
+            ],
+            "version": "==0.6.2"
+        },
         "gitdb2": {
             "hashes": [
                 "sha256:b60e29d4533e5e25bb50b7678bbc187c8f6bcff1344b4f293b2ba55c85795f09",
@@ -280,10 +300,16 @@
         },
         "parso": {
             "hashes": [
-                "sha256:8105449d86d858e53ce3e0044ede9dd3a395b1c9716c696af8aa3787158ab806",
-                "sha256:d250235e52e8f9fc5a80cc2a5f804c9fefd886b2e67a2b1099cf085f403f8e33"
+                "sha256:35704a43a3c113cce4de228ddb39aab374b8004f4f2407d070b6a2ca784ce8a2",
+                "sha256:895c63e93b94ac1e1690f5fdd40b65f07c8171e3e53cbd7793b5b96c0e0a7f24"
             ],
-            "version": "==0.3.0"
+            "version": "==0.3.1"
+        },
+        "pathtools": {
+            "hashes": [
+                "sha256:7c35c5421a39bb82e58018febd90e3b6e5db34c5443aaaf742b3f33d4655f1c0"
+            ],
+            "version": "==0.1.2"
         },
         "pbr": {
             "hashes": [
@@ -370,6 +396,13 @@
             "index": "pypi",
             "version": "==0.5.0"
         },
+        "pytest-watch": {
+            "hashes": [
+                "sha256:06136f03d5b361718b8d0d234042f7b2f203910d8568f63df2f866b547b3d4b9"
+            ],
+            "index": "pypi",
+            "version": "==4.2.0"
+        },
         "pyyaml": {
             "hashes": [
                 "sha256:254bf6fda2b7c651837acb2c718e213df29d531eebf00edb54743d10bcb694eb",
@@ -460,6 +493,12 @@
             "markers": "python_version < '3.7' and implementation_name == 'cpython'",
             "version": "==1.1.0"
         },
+        "watchdog": {
+            "hashes": [
+                "sha256:7e65882adb7746039b6f3876ee174952f8eaaa34491ba34333ddf1fe35de4162"
+            ],
+            "version": "==0.8.3"
+        },
         "wcwidth": {
             "hashes": [
                 "sha256:3df37372226d6e63e1b1e1eda15c594bca98a22d33a23832a90998faa96bc65e",
diff --git a/README.md b/README.md
index 64996466..d759de47 100644
--- a/README.md
+++ b/README.md
@@ -33,6 +33,10 @@ To run only the unit tests:
 
     pipenv run python -m pytest
 
+To re-run tests each time a file is changed:
+
+    pipenv run ptw
+
 ## Notes
 
 tornado templates are like mustache templates -- add the
diff --git a/tests/conftest.py b/tests/conftest.py
index d0da68f2..a8c45680 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -19,3 +19,23 @@ def app():
     deps.update(TEST_DEPS)
 
     return make_app(config, deps)
+
+class DummyForm(dict):
+    pass
+
+
+class DummyField(object):
+    def __init__(self, data=None, errors=(), raw_data=None):
+        self.data = data
+        self.errors = list(errors)
+        self.raw_data = raw_data
+
+
+@pytest.fixture
+def dummy_form():
+    return DummyForm()
+
+
+@pytest.fixture
+def dummy_field():
+    return DummyField()
diff --git a/tests/forms/test_validators.py b/tests/forms/test_validators.py
new file mode 100644
index 00000000..b648cc66
--- /dev/null
+++ b/tests/forms/test_validators.py
@@ -0,0 +1,61 @@
+from wtforms.validators import ValidationError
+import pytest
+
+from atst.forms.validators import Alphabet, IsNumber, PhoneNumber
+
+
+class TestIsNumber:
+
+    @pytest.mark.parametrize("valid", ["0", "12", "-12"])
+    def test_IsNumber_accepts_integers(self, valid, dummy_form, dummy_field):
+        validator = IsNumber()
+        dummy_field.data = valid
+        validator(dummy_form, dummy_field)
+
+    @pytest.mark.parametrize("invalid", ["12.1", "two", ""])
+    def test_IsNumber_rejects_anything_else(self, invalid, dummy_form, dummy_field):
+        validator = IsNumber()
+        dummy_field.data = invalid
+        with pytest.raises(ValidationError):
+            validator(dummy_form, dummy_field)
+
+
+class TestPhoneNumber:
+
+    @pytest.mark.parametrize("valid", [
+        "12345",
+        "1234567890",
+        "(123) 456-7890",
+    ])
+    def test_PhoneNumber_accepts_valid_numbers(self, valid, dummy_form, dummy_field):
+        validator = PhoneNumber()
+        dummy_field.data = valid
+        validator(dummy_form, dummy_field)
+
+    @pytest.mark.parametrize("invalid", [
+        "1234",
+        "123456",
+        "1234567abc",
+        "(123) 456-789012",
+    ])
+    def test_PhoneNumber_rejects_invalid_numbers(self, invalid, dummy_form, dummy_field):
+        validator = PhoneNumber()
+        dummy_field.data = invalid
+        with pytest.raises(ValidationError):
+            validator(dummy_form, dummy_field)
+
+
+class TestAlphabet:
+
+    @pytest.mark.parametrize("valid", ["a", "abcde"])
+    def test_Alphabet_accepts_letters(self, valid, dummy_form, dummy_field):
+        validator = Alphabet()
+        dummy_field.data = valid
+        validator(dummy_form, dummy_field)
+
+    @pytest.mark.parametrize("invalid", ["", "hi mark", "cloud9"])
+    def test_Alphabet_rejects_non_letters(self, invalid, dummy_form, dummy_field):
+        validator = Alphabet()
+        dummy_field.data = invalid
+        with pytest.raises(ValidationError):
+            validator(dummy_form, dummy_field)