TST: Ported tests from KnownArgumentNames.js

Ported from graphql/graphql-js/src/validation/__tests__/KnownArgumentNames.js,
these tests are currently failing as of this commit.

Tests are currently failing because the ``message`` method has not yet been
implemented in :class:`KnownArgumentNames` and :class:`KnownDirectives`.

Partial to #6

Author: woodb

tests/core_validation/test_known_argument_names.py

@@ -0,0 +1,125 @@
+from graphql.core.language.location import SourceLocation
+from graphql.core.validation.rules import KnownArgumentNames, KnownDirectives
+from utils import expect_passes_rule, expect_fails_rule
+
+
+def unknown_arg(arg_name, field_name, type_name, line, column):
+    return {
+        'message': KnownArgumentNames.message(arg_name, field_name, type_name),
+        'locations': [SourceLocation(line, column)]
+    }
+
+
+def unknown_directive_arg(arg_name, directive_name, line, column):
+    return {
+        'message': KnownDirectives.message(arg_name, directive_name),
+        'locations': [SourceLocation(line, column)]
+    }
+
+
+def test_single_arg_is_known():
+    expect_passes_rule(KnownArgumentNames, '''
+        fragment argOnRequiredArg on Dog {
+          doesKnowCommand(dogCommand: SIT)
+        }
+    ''')
+
+
+def test_multiple_args_are_known():
+    expect_passes_rule(KnownArgumentNames, '''
+      fragment multipleArgs on ComplicatedArgs {
+        multipleReqs(req1: 1, req2: 2)
+      }
+    ''')
+
+
+def test_ignore_args_of_unknown_fields():
+    expect_passes_rule(KnownArgumentNames, '''
+      fragment argOnUnknownField on Dog {
+        unknownField(unknownArg: SIT)
+      }
+    ''')
+
+
+def test_multiple_args_in_reverse_order_are_known():
+    expect_passes_rule(KnownArgumentNames, '''
+      fragment multipleArgsReverseOrder on ComplicatedArgs {
+        multipleReqs(req2: 2, req1: 1)
+      }
+    ''')
+
+
+def test_no_args_on_optional_arg():
+    expect_passes_rule(KnownArgumentNames, '''
+      fragment noArgOnOptionalArg on Dog {
+        isHousetrained
+      }
+    ''')
+
+
+def test_args_are_known_deeply():
+    expect_passes_rule(KnownArgumentNames, '''
+      {
+        dog {
+          doesKnowCommand(dogCommand: SIT)
+        }
+        human {
+          pet {
+            ... on Dog {
+                doesKnowCommand(dogCommand: SIT)
+            }
+          }
+        }
+      }
+    ''')
+
+
+def test_directive_args_are_known():
+    expect_passes_rule(KnownArgumentNames, '''
+      {
+        dog @skip(if: true)
+      }
+    ''')
+
+
+def test_undirective_args_are_invalid():
+    expect_fails_rule(KnownArgumentNames, '''
+      {
+        dog @skip(unless: true)
+      }
+    ''', [unknown_directive_arg('unless', 'skip', 3, 19)])
+
+
+def test_invalid_arg_name():
+    expect_fails_rule(KnownArgumentNames, '''
+      fragment invalidArgName on Dog {
+        doesKnowCommand(unknown: true)
+      }
+    ''', [unknown_arg('unknown', 'doesKnowCommand', 'Dog', 3, 25)])
+
+
+def test_unknown_args_amongst_known_args():
+    expect_fails_rule(KnownArgumentNames, '''
+      fragment oneGoodArgOneInvalidArg on Dog {
+        doesKnowCommand(whoknows: 1, dogCommand: SIT, unknown: true)
+      }
+    ''', [unknown_arg('whoknows', 'doesKnowCommand', 'Dog', 3, 25),
+          unknown_arg('unknown', 'doesKnowCommand', 'Dog', 3, 55)])
+
+
+def test_unknown_args_deeply():
+    expect_fails_rule(KnownArgumentNames, '''
+      {
+        dog {
+          doesKnowCommand(unknown: true)
+        }
+        human {
+          pet {
+            ... on Dog {
+              doesKnowCommand(unknown: true)
+            }
+          }
+        }
+      }
+    ''', [unknown_arg('unknown', 'doesKnowCommand', 'Dog', 4, 27),
+          unknown_arg('unknown', 'doesKnowCommand', 'Dog', 9, 31)])