diff --git a/zaqar/common/api/schemas/pools.py b/zaqar/common/api/schemas/pools.py
index 2a7765a59..ec9eee4d4 100644
--- a/zaqar/common/api/schemas/pools.py
+++ b/zaqar/common/api/schemas/pools.py
@@ -26,13 +26,13 @@ patch_options = {
     }
 }
 
-# NOTE(cpp-cabrera): a string valid for use in a URI
-# TODO(cpp-cabrera): perhaps validate this further using jsonschema's
-# uri validator as per rfc3987
 patch_uri = {
     'type': 'object', 'properties': {
         'uri': {
-            'type': 'string'
+            'type': 'string',
+            'minLength': 0,
+            'maxLength': 255,
+            'format': 'uri'
         },
         'additionalProperties': False
     }
@@ -41,7 +41,9 @@ patch_uri = {
 patch_group = {
     'type': 'object', 'properties': {
         'uri': {
-            'type': 'string'
+            'type': 'string',
+            'minLength': 0,
+            'maxLength': 255
         },
         'additionalProperties': False
     }
diff --git a/zaqar/tests/unit/transport/wsgi/v1/test_pools.py b/zaqar/tests/unit/transport/wsgi/v1/test_pools.py
index a194991fd..bea108939 100644
--- a/zaqar/tests/unit/transport/wsgi/v1/test_pools.py
+++ b/zaqar/tests/unit/transport/wsgi/v1/test_pools.py
@@ -63,12 +63,13 @@ def pools(test, count, uri):
     :returns: (paths, weights, uris, options)
     :rtype: ([six.text_type], [int], [six.text_type], [dict])
     """
+    mongo_url = uri
     base = test.url_prefix + '/pools/'
     args = [(base + str(i), i,
              {str(i): i})
             for i in range(count)]
     for path, weight, option in args:
-        uri = "%s/%s" % (uri, str(uuid.uuid4()))
+        uri = "%s/%s" % (mongo_url, str(uuid.uuid4()))
         doc = {'weight': weight, 'uri': uri, 'options': option}
         test.simulate_put(path, body=jsonutils.dumps(doc))
 
diff --git a/zaqar/tests/unit/transport/wsgi/v1_1/test_pools.py b/zaqar/tests/unit/transport/wsgi/v1_1/test_pools.py
index af91f434f..038bc2805 100644
--- a/zaqar/tests/unit/transport/wsgi/v1_1/test_pools.py
+++ b/zaqar/tests/unit/transport/wsgi/v1_1/test_pools.py
@@ -65,12 +65,13 @@ def pools(test, count, uri, group):
     :returns: (paths, weights, uris, options)
     :rtype: ([six.text_type], [int], [six.text_type], [dict])
     """
+    mongo_url = uri
     base = test.url_prefix + '/pools/'
     args = [(base + str(i), i,
              {str(i): i})
             for i in range(count)]
     for path, weight, option in args:
-        uri = "%s/%s" % (uri, str(uuid.uuid4()))
+        uri = "%s/%s" % (mongo_url, str(uuid.uuid4()))
         doc = {'weight': weight, 'uri': uri,
                'group': group, 'options': option}
         test.simulate_put(path, body=jsonutils.dumps(doc))
diff --git a/zaqar/tests/unit/transport/wsgi/v2_0/test_pools.py b/zaqar/tests/unit/transport/wsgi/v2_0/test_pools.py
index 80a7414c9..95e7bdec3 100644
--- a/zaqar/tests/unit/transport/wsgi/v2_0/test_pools.py
+++ b/zaqar/tests/unit/transport/wsgi/v2_0/test_pools.py
@@ -64,12 +64,13 @@ def pools(test, count, uri, group):
     :returns: (paths, weights, uris, options)
     :rtype: ([six.text_type], [int], [six.text_type], [dict])
     """
+    mongo_url = uri
     base = test.url_prefix + '/pools/'
     args = [(base + str(i), i,
              {str(i): i})
             for i in range(count)]
     for path, weight, option in args:
-        uri = "%s/%s" % (uri, str(uuid.uuid4()))
+        uri = "%s/%s" % (mongo_url, str(uuid.uuid4()))
         doc = {'weight': weight, 'uri': uri,
                'group': group, 'options': option}
         test.simulate_put(path, body=jsonutils.dumps(doc))