Validate and filter environment_names form input

atst/forms/new_project.py

@@ -1,9 +1,22 @@
 from flask_wtf import Form
-from wtforms.fields import StringField, TextAreaField
+from wtforms.fields import StringField, TextAreaField, FieldList
+from wtforms.validators import Required
+from atst.forms.validators import ListItemRequired
 
 
 class NewProjectForm(Form):
 
-    name = StringField(label="Project Name")
-    description = TextAreaField(label="Description")
-    environment_name = StringField(label="Environment Name")
+    EMPTY_ENVIRONMENT_NAMES = ["", None]
+
+    name = StringField(label="Project Name", validators=[Required()])
+    description = TextAreaField(label="Description", validators=[Required()])
+    environment_names = FieldList(
+        StringField(label="Environment Name"),
+        validators=[ListItemRequired(message="Provide at least one environment name.")],
+    )
+
+    @property
+    def data(self):
+        _data = super(Form, self).data
+        _data["environment_names"] = [n for n in _data["environment_names"] if n not in self.EMPTY_ENVIRONMENT_NAMES]
+        return _data

atst/forms/validators.py

@@ -51,3 +51,14 @@ def Alphabet(message="Please enter only letters."):
             raise ValidationError(message)
 
     return _alphabet
+
+
+def ListItemRequired(message="Please provide at least one.", empty_values=("", None)):
+    def _list_item_required(form, field):
+        non_empty_values = [v for v in field.data if v not in empty_values]
+        if len(non_empty_values) == 0:
+            raise ValidationError(message)
+
+    return _list_item_required
+
+