Expose AmountTaxScale by Web API

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+### 24.7.0 [#756](https://github.com/openfisca/openfisca-core/pull/756)
+
+- Exposes `amount` scales through the Web API
+  - Allows for [AmountTaxScale](https://github.com/openfisca/openfisca-core/blob/2b76b2ae5f684832411694c7c763b2d84c521c3c/openfisca_core/taxscales.py#L119) parameters to be consumed through the Web API
+  - See for an example this [parameter in openfisca-tunisia](https://github.com/openfisca/openfisca-tunisia/blob/10a15168e0aab5000f6850ad2f7779eba5da0fe0/openfisca_tunisia/parameters/impot_revenu/contribution_budget_etat.yaml)
+
 ### 24.6.8 [#753](https://github.com/openfisca/openfisca-core/pull/753)
 
 - Always allow `documentation` property for `ParameterNode`

openfisca_web_api/loader/parameters.py

@@ -25,15 +25,16 @@ def get_value(date, values):
         return None
 
 
-def build_api_scale(scale):
-    # preprocess brackets
+def build_api_scale(scale, value_key_name):
+    # preprocess brackets for a scale with 'rates' or 'amounts'
     brackets = [{
         'thresholds': build_api_values_history(bracket.threshold),
-        'rates': build_api_values_history(bracket.rate),
+        'values': build_api_values_history(getattr(bracket, value_key_name))
         } for bracket in scale.brackets]
 
     dates = set(sum(
-        [list(bracket['thresholds'].keys()) + list(bracket['rates'].keys()) for bracket in brackets],
+        [list(bracket['thresholds'].keys())
+        + list(bracket['values'].keys()) for bracket in brackets],
         []))  # flatten the dates and remove duplicates
 
     # We iterate on all dates as we need to build the whole scale for each of them
@@ -42,13 +43,14 @@ def build_api_scale(scale):
         for bracket in brackets:
             threshold_value = get_value(date, bracket['thresholds'])
             if threshold_value is not None:
-                rate_value = get_value(date, bracket['rates'])
+                rate_or_amount_value = get_value(date, bracket['values'])
                 api_scale[date] = api_scale.get(date) or {}
-                api_scale[date][threshold_value] = rate_value
+                api_scale[date][threshold_value] = rate_or_amount_value
 
     # Handle stopped parameters: a parameter is stopped if its first bracket is stopped
     latest_date_first_threshold = max(brackets[0]['thresholds'].keys())
     latest_value_first_threshold = brackets[0]['thresholds'][latest_date_first_threshold]
+
     if latest_value_first_threshold is None:
         api_scale[latest_date_first_threshold] = None
 
@@ -80,7 +82,10 @@ def walk_node(node, parameters, path_fragments, country_package_metadata):
                 api_parameter['documentation'] = child.documentation.strip()
             api_parameter['values'] = build_api_values_history(child)
         elif isinstance(child, Scale):
-            api_parameter['brackets'] = build_api_scale(child)
+            if 'rate' in child.brackets[0].children:
+                api_parameter['brackets'] = build_api_scale(child, 'rate')
+            elif 'amount' in child.brackets[0].children:
+                api_parameter['brackets'] = build_api_scale(child, 'amount')
         elif isinstance(child, ParameterNode):
             if child.documentation:
                 api_parameter['documentation'] = child.documentation.strip()
@@ -93,6 +98,8 @@ def walk_node(node, parameters, path_fragments, country_package_metadata):
             walk_node(child, parameters, path_fragments + [child_name], country_package_metadata)
         parameters.append(api_parameter)
 
+    return parameters
+
 
 def build_parameters(tax_benefit_system, country_package_metadata):
     original_parameters = tax_benefit_system.parameters

setup.py

@@ -35,7 +35,7 @@
 
 setup(
     name = 'OpenFisca-Core',
-    version = '24.6.8',
+    version = '24.7.0',
     author = 'OpenFisca Team',
     author_email = 'contact@openfisca.org',
     classifiers = [

tests/web_api/loader/test_parameters.py

@@ -0,0 +1,50 @@
+# -*- coding: utf-8 -*-
+
+import pytest
+
+from openfisca_core.parameters import ParameterNode, Scale
+
+from openfisca_web_api.loader.parameters import build_api_scale, walk_node
+
+
+def test_build_rate_scale():
+    '''Extracts a 'rate' children from a bracket collection'''
+    data = {'brackets': [{'rate': {'2014-01-01': {'value': 0.5}}, 'threshold': {'2014-01-01': {'value': 1}}}]}
+    rate = Scale('this rate', data, None)
+    assert build_api_scale(rate, 'rate') == {'2014-01-01': {1: 0.5}}
+
+
+def test_build_amount_scale():
+    '''Extracts an 'amount' children from a bracket collection'''
+    data = {'brackets': [{'amount': {'2014-01-01': {'value': 0}}, 'threshold': {'2014-01-01': {'value': 1}}}]}
+    rate = Scale('that amount', data, None)
+    assert build_api_scale(rate, 'amount') == {'2014-01-01': {1: 0}}
+
+
+@pytest.fixture
+def walk_node_args():
+    parameters = []
+    path_fragments = []
+    country_package_metadata = {'location': 'foo', 'version': '1', 'repository_url': 'foo'}
+
+    return parameters, path_fragments, country_package_metadata
+
+
+def test_walk_node_rate_scale(walk_node_args):
+    '''Serializes a 'rate' parameter node'''
+    root_node = ParameterNode(data = {})
+    data = {'brackets': [{'rate': {'2014-01-01': {'value': 0.5}}, 'threshold': {'2014-01-01': {'value': 1}}}]}
+    scale = Scale('this rate', data, None)
+    root_node.children['rate'] = scale
+    parameters = walk_node(root_node, *walk_node_args)
+    assert parameters == [{'description': None, 'id': 'rate', 'metadata': {}, 'brackets': {'2014-01-01': {1: 0.5}}}]
+
+
+def test_walk_node_amount_scale(walk_node_args):
+    '''Serializes an 'amount' parameter node'''
+    root_node = ParameterNode(data = {})
+    data = {'brackets': [{'amount': {'2014-01-01': {'value': 0}}, 'threshold': {'2014-01-01': {'value': 1}}}]}
+    scale = Scale('that amount', data, None)
+    root_node.children['amount'] = scale
+    parameters = walk_node(root_node, *walk_node_args)
+    assert parameters == [{'description': None, 'id': 'amount', 'metadata': {}, 'brackets': {'2014-01-01': {1: 0}}}]