TST: Add tests for stacklevel in warnings and "ignore" filters.

Enforces that stacklevel is used in warnings.warn and "ignore"
is not used in filterwarnings or simplefilter for most of numpy.

3 files changed, 91 insertions, 5 deletions

diff --git a/numpy/distutils/command/egg_info.py b/numpy/distutils/command/egg_info.py
index 972a27df3..7176f9212 100644
--- a/numpy/distutils/command/egg_info.py
+++ b/numpy/distutils/command/egg_info.py
@@ -10,7 +10,7 @@ class egg_info(_egg_info):
             import warnings
             warnings.warn("`build_src` is being run, this may lead to missing "
                           "files in your sdist!  See numpy issue gh-7127 for "
-                          "details", UserWarning)
+                          "details", UserWarning, stacklevel=2)
 
         # We need to ensure that build_src has been executed in order to give
         # setuptools' egg_info command real filenames instead of functions which
diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index cbab5ad5b..7cac90628 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -2450,12 +2450,12 @@ class TestMaskedArrayInPlaceArithmetics(TestCase):
                     x /= t(2)
                     assert_equal(x, y)
                 except (DeprecationWarning, TypeError) as e:
-                    warnings.warn(str(e))
+                    warnings.warn(str(e), stacklevel=1)
                 try:
                     xm /= t(2)
                     assert_equal(xm, y)
                 except (DeprecationWarning, TypeError) as e:
-                    warnings.warn(str(e))
+                    warnings.warn(str(e), stacklevel=1)
 
                 if issubclass(t, np.integer):
                     assert_equal(len(sup.log), 2, "Failed on type=%s." % t)
@@ -2485,7 +2485,7 @@ class TestMaskedArrayInPlaceArithmetics(TestCase):
                     x /= a
                     assert_equal(x, y / a)
                 except (DeprecationWarning, TypeError) as e:
-                    warnings.warn(str(e))
+                    warnings.warn(str(e), stacklevel=1)
                 try:
                     xm /= a
                     assert_equal(xm, y / a)
@@ -2494,7 +2494,7 @@ class TestMaskedArrayInPlaceArithmetics(TestCase):
                         mask_or(mask_or(m, a.mask), (a == t(0)))
                     )
                 except (DeprecationWarning, TypeError) as e:
-                    warnings.warn(str(e))
+                    warnings.warn(str(e), stacklevel=1)
 
                 if issubclass(t, np.integer):
                     assert_equal(len(sup.log), 2, "Failed on type=%s." % t)
diff --git a/numpy/tests/test_warnings.py b/numpy/tests/test_warnings.py
new file mode 100644
index 000000000..dcae60a81
--- /dev/null
+++ b/numpy/tests/test_warnings.py
@@ -0,0 +1,86 @@
+"""
+Tests which scan for certain occurances in the code, they may not find
+all of these occurances but should catch almost all.
+"""
+
+
+from __future__ import division, absolute_import, print_function
+
+
+import sys
+if sys.version_info >= (3, 4):
+    from pathlib import Path
+    import ast
+    import tokenize
+    import numpy
+    from numpy.testing import run_module_suite
+    from numpy.testing.decorators import slow
+
+
+    class ParseCall(ast.NodeVisitor):
+        def __init__(self):
+            self.ls = []
+
+        def visit_Attribute(self, node):
+            ast.NodeVisitor.generic_visit(self, node)
+            self.ls.append(node.attr)
+
+        def visit_Name(self, node):
+            self.ls.append(node.id)
+
+
+    class FindFuncs(ast.NodeVisitor):
+        def __init__(self, filename):
+            super().__init__()
+            self.__filename = filename
+
+        def visit_Call(self, node):
+            p = ParseCall()
+            p.visit(node.func)
+            ast.NodeVisitor.generic_visit(self, node)
+
+            if p.ls[-1] == 'simplefilter' or p.ls[-1] == 'filterwarnings':
+                if node.args[0].s == "ignore":
+                    raise AssertionError(
+                        "ignore filter should not be used; found in "
+                        "{} on line {}".format(self.__filename, node.lineno))
+
+            if p.ls[-1] == 'warn' and (
+                    len(p.ls) == 1 or p.ls[-2] == 'warnings'):
+
+                if "testing/tests/test_warnings.py" is self.__filename:
+                    # This file
+                    return
+
+                # See if stacklevel exists:
+                if len(node.args) == 3:
+                    return
+                args = {kw.arg for kw in node.keywords}
+                if "stacklevel" in args:
+                    return
+                raise AssertionError(
+                    "warnings should have an appropriate stacklevel; found in "
+                    "{} on line {}".format(self.__filename, node.lineno))
+
+
+    @slow
+    def test_warning_calls():
+        # combined "ignore" and stacklevel error
+        base = Path(numpy.__file__).parent
+
+        for path in base.rglob("*.py"):
+            if base / "testing" in path.parents:
+                continue
+            if path == base / "__init__.py":
+                continue
+            if path == base / "random" / "__init__.py":
+                continue
+            # use tokenize to auto-detect encoding on systems where no
+            # default encoding is defined (e.g. LANG='C')
+            with tokenize.open(str(path)) as file:
+                tree = ast.parse(file.read())
+                FindFuncs(path).visit(tree)
+
+
+    if __name__ == "__main__":
+        run_module_suite()