ASCII char classes: a few more tests

Author: wooster0

lib/std/ascii.zig

@@ -219,18 +219,21 @@ test "ASCII character classes" {
     try testing.expect(isAlphanumeric('Z'));
     try testing.expect(isAlphanumeric('z'));
     try testing.expect(isAlphanumeric('5'));
-    try testing.expect(isAlphanumeric('5'));
+    try testing.expect(isAlphanumeric('a'));
     try testing.expect(!isAlphanumeric('!'));
 
     try testing.expect(!isAlphabetic('5'));
     try testing.expect(isAlphabetic('c'));
-    try testing.expect(!isAlphabetic('5'));
+    try testing.expect(!isAlphabetic('@'));
+    try testing.expect(isAlphabetic('Z'));
 
     try testing.expect(isWhitespace(' '));
     try testing.expect(isWhitespace('\t'));
     try testing.expect(isWhitespace('\r'));
     try testing.expect(isWhitespace('\n'));
+    try testing.expect(isWhitespace(control_code.ff));
     try testing.expect(!isWhitespace('.'));
+    try testing.expect(!isWhitespace(control_code.us));
 
     try testing.expect(!isHex('g'));
     try testing.expect(isHex('b'));