Add a hypothesis test. Mostly checks libffi, or our own libffi_msvc on windows

1 files changed, 89 insertions, 0 deletions

diff --git a/testing/cffi0/test_function_args.py b/testing/cffi0/test_function_args.py
new file mode 100644
index 0000000..ed94c97
--- /dev/null
+++ b/testing/cffi0/test_function_args.py
@@ -0,0 +1,89 @@
+import pytest
+try:
+    from hypothesis import given
+    from hypothesis import strategies as st
+except ImportError as e:
+    def test_types():
+        pytest.skip(str(e))
+else:
+
+    from cffi import FFI
+    import random
+
+    ALL_PRIMITIVES = [
+        'unsigned char',
+        'short',
+        'int',
+        'long',
+        'long long',
+        'float',
+        'double',
+        'long double',
+    ]
+    def _make_struct(s):
+        return st.lists(s, min_size=1)
+    types = st.recursive(st.sampled_from(ALL_PRIMITIVES), _make_struct)
+
+    def draw_primitive(ffi, typename):
+        value = random.random() * 2**40
+        if typename != 'long double':
+            return ffi.cast(typename, value)
+        else:
+            return value
+
+
+    @given(st.lists(types), types)
+    def test_types(tp_args, tp_result):
+        cdefs = []
+        structs = {}
+
+        def build_type(tp):
+            if type(tp) is list:
+                field_types = [build_type(tp1) for tp1 in tp]
+                fields = ['%s f%d;' % (ftp, j)
+                          for (j, ftp) in enumerate(field_types)]
+                fields = '\n    '.join(fields)
+                name = 's%d' % len(cdefs)
+                cdefs.append("typedef struct {\n    %s\n} %s;" % (fields, name))
+                structs[name] = field_types
+                return name
+            else:
+                return tp
+
+        args = [build_type(tp) for tp in tp_args]
+        result = build_type(tp_result)
+
+        ffi = FFI()
+        ffi.cdef("\n".join(cdefs))
+
+        def make_arg(tp):
+            if tp in structs:
+                return [make_arg(tp1) for tp1 in structs[tp]]
+            else:
+                return draw_primitive(ffi, tp)
+
+        passed_args = [make_arg(arg) for arg in args]
+        returned_value = make_arg(result)
+        received_arguments = []
+
+        _tp_long_double = ffi.typeof("long double")
+        def expand(value):
+            if isinstance(value, ffi.CData):
+                t = ffi.typeof(value)
+                if t is _tp_long_double:
+                    return float(ffi.cast("double", value))
+                return [expand(getattr(value, 'f%d' % i))
+                        for i in range(len(t.fields))]
+            else:
+                return value
+
+        def callback(*args):
+            received_arguments.append([expand(arg) for arg in args])
+            return returned_value
+
+        fptr = ffi.callback("%s(*)(%s)" % (result, ','.join(args)), callback)
+        received_return = fptr(*passed_args)
+
+        assert len(received_arguments) == 1
+        assert passed_args == received_arguments[0]
+        assert expand(received_return) == returned_value