Begin conformance test

I'm not sure the details of this strategy can actually be made to work.
But, something can.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/Graphemes.zig b/src/Graphemes.zig
index 1ce1ea6..1f67fc6 100644
--- a/src/Graphemes.zig
+++ b/src/Graphemes.zig
@@ -364,3 +364,25 @@ test "Segmentation ZWJ and ZWSP emoji sequences" {
         try std.testing.expectEqual(@as(usize, 2), i);
     }
 }
+
+test "Iterator.peek" {
+    const peek_seq = "aΔ👨🏻‍🌾→";
+    const data = try Graphemes.init(std.testing.allocator);
+    defer data.deinit(std.testing.allocator);
+
+    var iter = data.iterator(peek_seq);
+    const peek_a = iter.peek().?;
+    const next_a = iter.next().?;
+    try std.testing.expectEqual(peek_a, next_a);
+    try std.testing.expectEqualStrings("a", peek_a.bytes(peek_seq));
+    const peek_d1 = iter.peek().?;
+    const peek_d2 = iter.peek().?;
+    try std.testing.expectEqual(peek_d1, peek_d2);
+    const next_d = iter.next().?;
+    try std.testing.expectEqual(peek_d2, next_d);
+    try std.testing.expectEqual(iter.peek(), iter.next());
+    try std.testing.expectEqual(iter.peek(), iter.next());
+    try std.testing.expectEqual(null, iter.peek());
+    try std.testing.expectEqual(null, iter.peek());
+    try std.testing.expectEqual(iter.peek(), iter.next());
+}