util.uuid: Add UUIDv7

Allows sorting by id as a substitute for sorting by timestamp since it
has the timestamp in the encoded in the first part, and only things that
happen extremely close together may get out of order by such a sort,
which might not matter.

From draft-ietf-uuidrev-rfc4122bis formerly draft-peabody-dispatch-new-uuid-format

1 files changed, 22 insertions, 0 deletions

diff --git a/spec/util_uuid_spec.lua b/spec/util_uuid_spec.lua
index 46400d00..7157d0ec 100644
--- a/spec/util_uuid_spec.lua
+++ b/spec/util_uuid_spec.lua
@@ -20,6 +20,28 @@ describe("util.uuid", function()
 			for _ = 1, 100 do
 				assert.is_string(uuid.generate():match(pattern));
 			end
+
+			assert.truthy(uuid.generate() ~= uuid.generate(), "does not generate the same UUIDv4 twice")
+		end);
+	end);
+	describe("#v7", function()
+		it("should also follow the UUID pattern", function()
+			local pattern = "^" .. table.concat({
+					string.rep("%x", 8),
+					string.rep("%x", 4),
+					"7" .. -- version
+					string.rep("%x", 3),
+					"[89ab]" .. -- reserved bits of 1 and 0
+					string.rep("%x", 3),
+					string.rep("%x", 12),
+				}, "%-") .. "$";
+
+			local one = uuid.v7(); -- one before the loop to ensure some time passes
+			for _ = 1, 100 do
+				assert.is_string(uuid.v7():match(pattern));
+			end
+			-- one after the loop when some time should have passed
+			assert.truthy(one < uuid.v7(), "should be ordererd")
 		end);
 	end);
 end);