diff --git a/tests/io/file1.py b/tests/io/file1.py
index 7d5154a4f8..c46c081b80 100644
--- a/tests/io/file1.py
+++ b/tests/io/file1.py
@@ -4,3 +4,11 @@ print(f.readline())
 print(f.read())
 f = open("io/data/file1")
 print(f.readlines())
+f = open("io/data/file1","r")
+print(f.readlines())
+f = open("io/data/file1","rb")
+print(f.readlines())
+f = open("io/data/file1",mode="r")
+print(f.readlines())
+f = open("io/data/file1",mode="rb")
+print(f.readlines())
diff --git a/tests/unicode/file1.py b/tests/unicode/file1.py
index 554e886743..08b7d25041 100644
--- a/tests/unicode/file1.py
+++ b/tests/unicode/file1.py
@@ -1,4 +1,4 @@
-f = open("unicode/data/utf-8_1.txt")
+f = open("unicode/data/utf-8_1.txt", encoding="utf-8")
 l = f.readline()
 print(l)
 print(len(l))
diff --git a/tests/unicode/file2.py b/tests/unicode/file2.py
index aca2e0e0ed..b8a3419660 100644
--- a/tests/unicode/file2.py
+++ b/tests/unicode/file2.py
@@ -1,7 +1,11 @@
 # test reading a given number of characters
 
 def do(mode):
-    f = open('unicode/data/utf-8_2.txt', mode)
+    if mode == 'rb':
+        enc = None
+    else:
+        enc = 'utf-8'
+    f = open('unicode/data/utf-8_2.txt', mode=mode, encoding=enc)
     print(f.read(1))
     print(f.read(1))
     print(f.read(2))