Add tests for overflows converting ints to bytes

Author: Matt Wozniski

tests/basics/array_overflow.py

@@ -0,0 +1,35 @@
+import skip_if
+skip_if.no_bigint()
+
+try:
+    from array import array
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+def test_array_overflow(typecode, val):
+    try:
+        print(array(typecode, [val]))
+    except OverflowError:
+        print('OverflowError')
+
+# small int -1
+test_array_overflow('Q', -1)
+test_array_overflow('L', -1)
+test_array_overflow('I', -1)
+test_array_overflow('H', -1)
+test_array_overflow('B', -1)
+
+# big int -1
+test_array_overflow('Q', -2**64 // 2**64)
+test_array_overflow('L', -2**64 // 2**64)
+test_array_overflow('I', -2**64 // 2**64)
+test_array_overflow('H', -2**64 // 2**64)
+test_array_overflow('B', -2**64 // 2**64)
+
+# big int 2**63
+test_array_overflow('q', 2**63)
+test_array_overflow('l', 2**63)
+test_array_overflow('i', 2**63)
+test_array_overflow('h', 2**63)
+test_array_overflow('b', 2**63)

tests/basics/int_bytes.py

@@ -17,3 +17,15 @@
     (1).to_bytes(-1, "little")
 except ValueError:
     print("ValueError")
+
+# too small buffer should raise an error
+try:
+    (256).to_bytes(1, "little")
+except OverflowError:
+    print("OverflowError")
+
+# negative numbers should raise an error
+try:
+    (-256).to_bytes(2, "little")
+except OverflowError:
+    print("OverflowError")

tests/basics/int_bytes_intbig.py

@@ -15,3 +15,15 @@
 
 # check that extra zero bytes don't change the internal int value
 print(int.from_bytes(b + bytes(10), "little") == int.from_bytes(b, "little"))
+
+# too small buffer should raise an error
+try:
+    (2**64).to_bytes(8, "little")
+except OverflowError:
+    print("OverflowError")
+
+# negative numbers should raise an error
+try:
+    (-2**64).to_bytes(9, "little")
+except OverflowError:
+    print("OverflowError")

tests/basics/struct_overflow.py

@@ -0,0 +1,47 @@
+import skip_if
+skip_if.no_bigint()
+
+try:
+    import ustruct as struct
+except:
+    try:
+        import struct
+    except ImportError:
+        print("SKIP")
+        raise SystemExit
+
+def test_struct_overflow(typecode, val):
+    try:
+        print(struct.pack(typecode, val))
+    except OverflowError:
+        print('OverflowError')
+    except struct.error:
+        print('OverflowError')
+
+# small int -1
+test_struct_overflow('>Q', -1)
+test_struct_overflow('>L', -1)
+test_struct_overflow('>I', -1)
+test_struct_overflow('>H', -1)
+test_struct_overflow('>B', -1)
+
+# big int -1
+test_struct_overflow('>Q', -2**64 // 2**64)
+test_struct_overflow('>L', -2**64 // 2**64)
+test_struct_overflow('>I', -2**64 // 2**64)
+test_struct_overflow('>H', -2**64 // 2**64)
+test_struct_overflow('>B', -2**64 // 2**64)
+
+# possibly small ints
+test_struct_overflow('>q', 2**63)
+test_struct_overflow('>l', 2**31)
+test_struct_overflow('>i', 2**31)
+test_struct_overflow('>h', 2**15)
+test_struct_overflow('>b', 2**7)
+
+# definitely big ints
+test_struct_overflow('>q', 2**64 // 2**1)
+test_struct_overflow('>l', 2**64 // 2**33)
+test_struct_overflow('>i', 2**64 // 2**33)
+test_struct_overflow('>h', 2**64 // 2**49)
+test_struct_overflow('>b', 2**64 // 2**57)