tests/basics: Use str.format instead of % for formatting messages.

Only use % formatting when testing % itself, because only str.format is
guaranteed to be available on any port.

tests/basics/async_await2.py

@@ -11,7 +11,7 @@ else:
 @coroutine
 def wait(value):
     print('wait value:', value)
-    msg = yield 'message from wait(%u)' % value
+    msg = yield 'message from wait({})'.format(value)
     print('wait got back:', msg)
     return 10
 

tests/basics/class_inplace_op.py

@@ -10,7 +10,7 @@ class A:
         return A(self.v + o.v)
 
     def __repr__(self):
-        return "A(%s)" % self.v
+        return "A({})".format(self.v)
 
 a = A(5)
 b = a
@@ -37,7 +37,7 @@ class L:
         return self
 
     def __repr__(self):
-        return "L(%s)" % self.v
+        return "L({})".format(self.v)
 
 c = L([1, 2])
 d = c

tests/basics/class_notimpl.py

@@ -11,7 +11,7 @@ class C:
         self.value = value
 
     def __str__(self):
-        return "C(%s)" % self.value
+        return "C({})".format(self.value)
 
     def __add__(self, rhs):
         print(self, '+', rhs)

tests/basics/class_reverse_op.py

@@ -12,7 +12,7 @@ class A:
         return A(self.v + o)
 
     def __repr__(self):
-        return "A(%s)" % self.v
+        return "A({})".format(self.v)
 
 print(A(3) + 1)
 print(2 + A(5))

tests/basics/string_repr.py

@@ -1,4 +1,4 @@
 # anything above 0xa0 is printed as Unicode by CPython
 # the abobe is CPython implementation detail, stick to ASCII
 for c in range(0x80):
-    print("0x%02x: %s" % (c, repr(chr(c))))
+    print("0x{:02x}: {}".format(c, repr(chr(c))))