Adding unit tests for shared memory

tests/test_shared_memory.py

@@ -0,0 +1,56 @@
+import unittest
+
+from wasmtime import *
+
+
+class TestSharedMemory(unittest.TestCase):
+    def test_new(self):
+        engine = Store().engine
+        memory_type = MemoryType(Limits(1, 2), is_64=False, shared=True)
+        assert(not memory_type.is_64)
+        shared_memory = SharedMemory(engine, memory_type)
+        with self.assertRaises(TypeError):
+            shared_memory.grow('')  # type: ignore
+        with self.assertRaises(WasmtimeError):
+            shared_memory.grow(-1)
+        self.assertEqual(shared_memory.data_ptr()[0], 0)
+        self.assertEqual(shared_memory.data_len(), 65536)
+        self.assertTrue(isinstance(shared_memory.type(), MemoryType))
+
+    def test_grow(self):
+        engine = Store().engine
+        memory_type = MemoryType(Limits(1, 2), shared=True)
+        shared_memory = SharedMemory(engine, memory_type)
+        assert(shared_memory.grow(1) == 1)
+        assert(shared_memory.grow(0) == 2)
+        with self.assertRaises(WasmtimeError):
+            shared_memory.grow(1)
+
+    def test_errors(self):
+        engine = Store().engine
+        ty = MemoryType(Limits(1, 2), shared=True)
+        with self.assertRaises(AttributeError):
+            SharedMemory(1, ty)  # type: ignore
+        with self.assertRaises(AttributeError):
+            SharedMemory(engine, 1)  # type: ignore
+
+    def test_shared_memory_type_fails_if_no_max_specified(self):
+        with self.assertRaises(WasmtimeError):
+            # Shared memories must have a max size
+            MemoryType(Limits(0x100000000, None), shared=True)
+
+    def test_shared_memory_type_works_if_min_max_i64_is_set(self):
+        ty = MemoryType(Limits(0x100000000, 0x100000000), is_64=True, shared=True)
+        assert(ty.limits.min == 0x100000000)
+        assert(ty.limits.max == 0x100000000)
+        assert(ty.is_64)
+
+    def test_shared_memory_type_fails_if_is_too_large(self):
+        with self.assertRaises(WasmtimeError):
+            MemoryType(Limits(1, 0x100000000), shared=True)
+
+    def test_memory_type_has_to_be_shared(self):
+        engine = Store().engine
+        ty = MemoryType(Limits(1, 2))
+        with self.assertRaises(WasmtimeError):
+            SharedMemory(engine, ty)