test: improve commons module doctests

CHANGELOG.md

@@ -1,5 +1,16 @@
 # Changelog
 
+### 35.5.4 [#1033](https://github.com/openfisca/openfisca-core/pull/1033)
+
+#### Bug Fixes
+
+- Fix doctests of the commons module
+
+#### Dependencies
+
+- `darglint`, `flake8-docstrings`, & `pylint`
+  - For automatic docstring linting & validation.
+
 ### 35.5.3 [#1020](https://github.com/openfisca/openfisca-core/pull/1020)
 
 #### Technical changes

openfisca_core/commons/formulas.py

@@ -5,17 +5,15 @@ def apply_thresholds(input, thresholds, choices):
     """
     Return one of the choices depending on the input position compared to thresholds, for each input.
 
-    >>> apply_thresholds(np.array([4]), [5, 7], [10, 15, 20])
-    array([10])
-    >>> apply_thresholds(np.array([5]), [5, 7], [10, 15, 20])
-    array([10])
-    >>> apply_thresholds(np.array([6]), [5, 7], [10, 15, 20])
-    array([15])
-    >>> apply_thresholds(np.array([8]), [5, 7], [10, 15, 20])
-    array([20])
-    >>> apply_thresholds(np.array([10]), [5, 7, 9], [10, 15, 20])
-    array([0])
+    Examples:
+        >>> input = numpy.array([4, 5, 6, 7, 8])
+        >>> thresholds = [5, 7]
+        >>> choices = [10, 15, 20]
+        >>> apply_thresholds(input, thresholds, choices)
+        array([10, 10, 15, 15, 20])
+
     """
+
     condlist = [input <= threshold for threshold in thresholds]
     if len(condlist) == len(choices) - 1:
         # If a choice is provided for input > highest threshold, last condition must be true to return it.
@@ -26,6 +24,16 @@ def apply_thresholds(input, thresholds, choices):
 
 
 def concat(this, that):
+    """
+
+    Examples:
+        >>> this = ["this", "that"]
+        >>> that = numpy.array([1, 2.5])
+        >>> concat(this, that)
+        array(['this1.0', 'that2.5']...)
+
+    """
+
     if isinstance(this, numpy.ndarray) and not numpy.issubdtype(this.dtype, numpy.str):
         this = this.astype('str')
     if isinstance(that, numpy.ndarray) and not numpy.issubdtype(that.dtype, numpy.str):
@@ -39,10 +47,14 @@ def switch(conditions, value_by_condition):
     Reproduces a switch statement: given an array of conditions, return an array of the same size replacing each
     condition item by the corresponding given value.
 
-    Example:
-        >>> switch(np.array([1, 1, 1, 2]), {1: 80, 2: 90})
+    Examples:
+        >>> conditions = numpy.array([1, 1, 1, 2])
+        >>> value_by_condition = {1: 80, 2: 90}
+        >>> switch(conditions, value_by_condition)
         array([80, 80, 80, 90])
+
     '''
+
     assert len(value_by_condition) > 0, \
         "switch must be called with at least one value"
     condlist = [

openfisca_core/commons/misc.py

@@ -2,7 +2,23 @@
 
 
 def empty_clone(original):
-    """Create a new empty instance of the same class of the original object."""
+    """Create a new empty instance of the same class of the original object.
+
+    Examples:
+        >>> Foo = type("Foo", (list,), {})
+        >>> foo = Foo([1, 2, 3])
+        >>> foo
+        [1, 2, 3]
+
+        >>> bar = empty_clone(foo)
+        >>> bar
+        []
+
+        >>> isinstance(bar, Foo)
+        True
+
+    """
+
     class Dummy(original.__class__):
         def __init__(self) -> None:
             pass
@@ -15,6 +31,24 @@ def __init__(self) -> None:
 def stringify_array(array: numpy.ndarray) -> str:
     """
     Generate a clean string representation of a NumPY array.
+
+    Examples:
+        >>> import numpy
+        >>> stringify_array(None)
+        'None'
+
+        >>> array = numpy.array([10, 20.])
+        >>> stringify_array(array)
+        '[10.0, 20.0]'
+
+        >>> array = numpy.array(["10", "Twenty"])
+        >>> stringify_array(array)
+        '[10, Twenty]'
+
+        >>> array = numpy.array([list, dict(), stringify_array])
+        >>> stringify_array(array)
+        "[<class 'list'>, {}, <function stringify_array...]"
+
     """
 
     if array is None:

openfisca_core/commons/rates.py

@@ -8,7 +8,16 @@ def average_rate(target = None, varying = None, trim = None):
     :param target: Targeted net income, numerator
     :param varying: Varying gross income, denominator
     :param trim: Lower and upper bound of average rate to return
+
+    Examples:
+        >>> target = numpy.array([1, 2, 3])
+        >>> varying = [2, 2, 2]
+        >>> trim = [-1, .25]
+        >>> average_rate(target, varying, trim)
+        array([ nan,  0. , -0.5])
+
     '''
+
     average_rate = 1 - target / varying
     if trim is not None:
         average_rate = numpy.where(average_rate <= max(trim), average_rate, numpy.nan)
@@ -18,6 +27,17 @@ def average_rate(target = None, varying = None, trim = None):
 
 
 def marginal_rate(target = None, varying = None, trim = None):
+    """
+
+    Examples:
+        >>> target = numpy.array([1, 2, 3])
+        >>> varying = numpy.array([1, 2, 4])
+        >>> trim = [.25, .75]
+        >>> marginal_rate(target, varying, trim)
+        array([nan, 0.5])
+
+    """
+
     # target: numerator, varying: denominator
     marginal_rate = 1 - (target[:-1] - target[1:]) / (varying[:-1] - varying[1:])
     if trim is not None:

openfisca_core/commons/tests/test_dummy.py

@@ -0,0 +1,10 @@
+import pytest
+
+from openfisca_core.commons import Dummy
+
+
+def test_dummy_deprecation():
+    """Dummy throws a deprecation warning when instantiated."""
+
+    with pytest.warns(DeprecationWarning):
+        assert Dummy()

openfisca_core/commons/tests/test_formulas.py

@@ -0,0 +1,81 @@
+import numpy
+import pytest
+from numpy.testing import assert_array_equal
+
+from openfisca_core import commons
+
+
+def test_apply_thresholds_when_several_inputs():
+    """Makes a choice for any given input."""
+
+    input_ = numpy.array([4, 5, 6, 7, 8, 9, 10])
+    thresholds = [5, 7, 9]
+    choices = [10, 15, 20, 25]
+
+    result = commons.apply_thresholds(input_, thresholds, choices)
+
+    assert_array_equal(result, [10, 10, 15, 15, 20, 20, 25])
+
+
+def test_apply_thresholds_when_too_many_thresholds():
+    """Raises an AssertionError when thresholds > choices."""
+
+    input_ = numpy.array([6])
+    thresholds = [5, 7, 9, 11]
+    choices = [10, 15, 20]
+
+    with pytest.raises(AssertionError):
+        assert commons.apply_thresholds(input_, thresholds, choices)
+
+
+def test_apply_thresholds_when_too_many_choices():
+    """Raises an AssertionError when thresholds < choices - 1."""
+
+    input_ = numpy.array([6])
+    thresholds = [5, 7]
+    choices = [10, 15, 20, 25]
+
+    with pytest.raises(AssertionError):
+        assert commons.apply_thresholds(input_, thresholds, choices)
+
+
+def test_concat_when_this_is_array_not_str():
+    """Casts ``this`` to ``str`` when it is a numpy array other than string."""
+
+    this = numpy.array([1, 2])
+    that = numpy.array(["la", "o"])
+
+    result = commons.concat(this, that)
+
+    assert_array_equal(result, ["1la", "2o"])
+
+
+def test_concat_when_that_is_array_not_str():
+    """Casts ``that`` to ``str`` when it is a numpy array other than string."""
+
+    this = numpy.array(["ho", "cha"])
+    that = numpy.array([1, 2])
+
+    result = commons.concat(this, that)
+
+    assert_array_equal(result, ["ho1", "cha2"])
+
+
+def test_concat_when_args_not_str_array_like():
+    """Raises a TypeError when args are not a string array-like object."""
+
+    this = (1, 2)
+    that = (3, 4)
+
+    with pytest.raises(TypeError):
+        commons.concat(this, that)
+
+
+def test_switch_when_values_are_empty():
+    """Raises an AssertionError when the values are empty."""
+
+    conditions = [1, 1, 1, 2]
+    value_by_condition = {}
+
+    with pytest.raises(AssertionError):
+        assert commons.switch(conditions, value_by_condition)

openfisca_core/commons/tests/test_rates.py

@@ -0,0 +1,26 @@
+import numpy
+from numpy.testing import assert_array_equal
+
+from openfisca_core import commons
+
+
+def test_average_rate_when_varying_is_zero():
+    """Yields infinity when the varying gross income crosses zero."""
+
+    target = numpy.array([1, 2, 3])
+    varying = [0, 0, 0]
+
+    result = commons.average_rate(target, varying)
+
+    assert_array_equal(result, [- numpy.inf, - numpy.inf, - numpy.inf])
+
+
+def test_marginal_rate_when_varying_is_zero():
+    """Yields infinity when the varying gross income crosses zero."""
+
+    target = numpy.array([1, 2, 3])
+    varying = numpy.array([0, 0, 0])
+
+    result = commons.marginal_rate(target, varying)
+
+    assert_array_equal(result, [numpy.inf, numpy.inf])

openfisca_tasks/lint.mk

@@ -1,5 +1,5 @@
 ## Lint the codebase.
-lint: check-syntax-errors check-style check-types
+lint: check-syntax-errors check-style lint-doc check-types
 	@$(call print_pass,$@:)
 
 ## Compile python files to check for syntax errors.
@@ -14,10 +14,34 @@ check-style: $(shell git ls-files "*.py")
 	@flake8 $?
 	@$(call print_pass,$@:)
 
+## Run linters to check for syntax and style errors in the doc.
+lint-doc: \
+	lint-doc-commons \
+	lint-doc-types \
+	;
+
+## Run linters to check for syntax and style errors in the doc.
+lint-doc-%:
+	@## These checks are exclusively related to doc/strings/test.
+	@##
+	@## They can be integrated into setup.cfg once all checks pass.
+	@## The reason they're here is because otherwise we wouldn't be
+	@## able to integrate documentation improvements incrementally.
+	@##
+	@## D101:	Each class has to have at least one doctest.
+	@## D102:	Each public method has to have at least one doctest.
+	@## D103:	Each public function has to have at least one doctest.
+	@## DARXXX:	https://github.com/terrencepreilly/darglint#error-codes.
+	@##
+	@$(call print_help,$(subst $*,%,$@:))
+	@flake8 --select=D101,D102,D103,DAR openfisca_core/$*
+	@pylint openfisca_core/$*
+	@$(call print_pass,$@:)
+
 ## Run static type checkers for type errors.
-check-types: openfisca_core openfisca_web_api
+check-types:
 	@$(call print_help,$@:)
-	@mypy $?
+	@mypy --package openfisca_core --package openfisca_web_api
 	@$(call print_pass,$@:)
 
 ## Run code formatters to correct style errors.

openfisca_tasks/test_code.mk

@@ -19,7 +19,7 @@ test-code: test-core test-country test-extension
 ## Run openfisca-core tests.
 test-core: $(shell git ls-files "tests/*.py")
 	@$(call print_help,$@:)
-	@PYTEST_ADDOPTS="${PYTEST_ADDOPTS} --cov=openfisca_core ${pytest_args}" \
+	@PYTEST_ADDOPTS="${PYTEST_ADDOPTS} --cov=openfisca_core --cov=openfisca_web_api ${pytest_args}" \
 		openfisca test $? \
 		${openfisca_args}
 	@$(call print_pass,$@:)

openfisca_tasks/test_doc.mk

@@ -62,14 +62,17 @@ test-doc-checkout:
 			} \
 			|| git pull --ff-only origin master ; \
 	} 1> /dev/null
+	@$(call print_pass,$@:)
 
 ## Install doc dependencies.
 test-doc-install:
 	@$(call print_help,$@:)
 	@pip install --requirement doc/requirements.txt 1> /dev/null
 	@pip install --editable .[dev] --upgrade 1> /dev/null
+	@$(call print_pass,$@:)
 
 ## Dry-build the doc.
 test-doc-build:
 	@$(call print_help,$@:)
 	@sphinx-build -M dummy doc/source doc/build -n -q -W
+	@$(call print_pass,$@:)