Merge: Fix model_json and nitweb

Was broken since #2312

* Migrate `model_json` to new serialization API
* Add tests to `model_json` to ensure this doesn't happen anymore
* Migrate `web` package and `nitweb` to new API

@xymus a lot of serialization for you. Note: for each entity, I needed two deserialization version `full` and no full. Wasn't sure on how to handle this concern properly with your API

Pull-Request: #2327
Reviewed-by: Alexis Laferrière <[email protected]>

src/model/test_model_json.nit

@@ -0,0 +1,111 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module test_model_json is test_suite
+
+import test_suite
+import model_json
+import frontend
+
+class TestModelSerialization
+	super TestSuite
+
+	var suite_path: String = "NIT_TESTING_PATH".environ
+	var lib_path: String = "{suite_path.dirname}/../../tests/test_prog"
+
+	private var model: Model do
+		var toolcontext = new ToolContext
+		var model = new Model
+		var mbuilder = new ModelBuilder(model, toolcontext)
+		var mmodules = mbuilder.parse_full([lib_path])
+		if mmodules.is_empty then return model
+		mbuilder.run_phases
+		toolcontext.run_global_phases(mmodules)
+		return model
+	end
+
+	fun test_refs_to_full_json do
+		var mentities = new Array[MEntity]
+		mentities.add model.mpackages.first
+		mentities.add model.mmodules.first
+		mentities.add model.mclasses.first
+		for mentity in mentities do
+			print ((new MEntityRef(mentity)).to_pretty_full_json)
+		end
+	end
+
+	fun test_packages_to_full_json do
+		for mentity in model.mpackages do
+			print mentity.to_pretty_full_json
+		end
+	end
+
+	fun test_groups_to_full_json do
+		for mpackage in model.mpackages do
+			for mentity in mpackage.mgroups do
+				print mentity.to_pretty_full_json
+			end
+		end
+	end
+
+	fun test_modules_to_full_json do
+		for mentity in model.mmodules do
+			print mentity.to_pretty_full_json
+		end
+	end
+
+	fun test_classes_to_full_json do
+		for mentity in model.mclasses do
+			print mentity.to_pretty_full_json
+		end
+	end
+
+	fun test_classdefs_to_full_json do
+		for mclass in model.mclasses do
+			for mentity in mclass.mclassdefs do
+				print mentity.to_pretty_full_json
+			end
+		end
+	end
+
+	fun test_props_to_full_json do
+		for mentity in model.mproperties do
+			print mentity.to_pretty_full_json
+		end
+	end
+
+	fun test_propdefs_to_full_json do
+		for mprop in model.mproperties do
+			for mentity in mprop.mpropdefs do
+				print mentity.to_pretty_full_json
+			end
+		end
+	end
+end
+
+redef class Location
+	serialize
+
+	# Avoid diff on location absolute path
+	redef fun core_serialize_to(v) do
+		v.serialize_attribute("column_end", column_end)
+		v.serialize_attribute("column_start", column_start)
+		v.serialize_attribute("line_end", line_end)
+		v.serialize_attribute("line_start", line_start)
+		var file = self.file
+		if file != null then
+			v.serialize_attribute("file", "test_location")
+		end
+	end
+end