Added implementation for create-model,get-models,get-model in api gateway

tests/test_apigateway/test_apigateway.py

@@ -1547,6 +1547,148 @@ def test_get_domain_name():
     result["domainNameStatus"].should.equal("AVAILABLE")
 
 
+@mock_apigateway
+def test_create_model():
+    client = boto3.client("apigateway", region_name="us-west-2")
+    response = client.create_rest_api(name="my_api",
+                                      description="this is my api"
+                                      )
+    rest_api_id = response["id"]
+    dummy_rest_api_id = 'a12b3c4d'
+    model_name = "testModel"
+    description = "test model"
+    content_type = 'application/json'
+    # success case with valid params
+    response = client.create_model(
+        restApiId=rest_api_id,
+        name=model_name,
+        description=description,
+        contentType=content_type
+    )
+    response["name"].should.equal(model_name)
+    response["description"].should.equal(description)
+
+    # with an invalid rest_api_id it should throw NotFoundException
+    with assert_raises(ClientError) as ex:
+         client.create_model(
+            restApiId=dummy_rest_api_id,
+            name=model_name,
+            description=description,
+             contentType=content_type
+        )
+    ex.exception.response["Error"]["Message"].should.equal(
+        "Invalid Rest API Id specified"
+    )
+    ex.exception.response["Error"]["Code"].should.equal(
+        "NotFoundException"
+    )
+
+    with assert_raises(ClientError) as ex:
+         client.create_model(
+            restApiId=rest_api_id,
+            name="",
+            description=description,
+            contentType=content_type
+        )
+
+    ex.exception.response["Error"]["Message"].should.equal(
+        "No Model Name specified"
+    )
+    ex.exception.response["Error"]["Code"].should.equal(
+        "BadRequestException"
+    )
+
+
+@mock_apigateway
+def test_get_api_models():
+    client = boto3.client("apigateway", region_name="us-west-2")
+    response = client.create_rest_api(
+        name="my_api",
+        description="this is my api"
+        )
+    rest_api_id = response["id"]
+    model_name = "testModel"
+    description = "test model"
+    content_type = 'application/json'
+    # when no models are present
+    result = client.get_models(
+        restApiId=rest_api_id
+    )
+    result["items"].should.equal([])
+    # add a model
+    client.create_model(
+        restApiId=rest_api_id,
+        name=model_name,
+        description=description,
+        contentType=content_type
+    )
+    # get models after adding
+    result = client.get_models(
+        restApiId=rest_api_id
+    )
+    result["items"][0]["name"] = model_name
+    result["items"][0]["description"] = description
+
+
+@mock_apigateway
+def test_get_model_by_name():
+    client = boto3.client("apigateway", region_name="us-west-2")
+    response = client.create_rest_api(
+        name="my_api",
+        description="this is my api"
+    )
+    rest_api_id = response["id"]
+    dummy_rest_api_id = 'a12b3c4d'
+    model_name = "testModel"
+    description = "test model"
+    content_type = 'application/json'
+    # add a model
+    client.create_model(
+        restApiId=rest_api_id,
+        name=model_name,
+        description=description,
+        contentType=content_type
+    )
+    # get models after adding
+    result = client.get_model(
+        restApiId=rest_api_id, modelName=model_name
+    )
+    result["name"] = model_name
+    result["description"] = description
+
+    with assert_raises(ClientError) as ex:
+        client.get_model(
+            restApiId=dummy_rest_api_id, modelName=model_name
+        )
+    ex.exception.response["Error"]["Message"].should.equal(
+        "Invalid Rest API Id specified"
+    )
+    ex.exception.response["Error"]["Code"].should.equal(
+        "NotFoundException"
+    )
+
+
+@mock_apigateway
+def test_get_model_with_invalid_name():
+    client = boto3.client("apigateway", region_name="us-west-2")
+    response = client.create_rest_api(
+        name="my_api",
+        description="this is my api"
+        )
+    rest_api_id = response["id"]
+    # test with an invalid model name
+    with assert_raises(ClientError) as ex:
+        client.get_model(
+            restApiId=rest_api_id, modelName="fake"
+            )
+    ex.exception.response["Error"]["Message"].should.equal(
+        "Invalid Model Name specified"
+    )
+    ex.exception.response["Error"]["Code"].should.equal(
+        "NotFoundException"
+    )
+
+
 @mock_apigateway
 def test_http_proxying_integration():
     responses.add(