spec: Add spec for BinaryParser::ByteSize

Author: DanSnow

spec/byte_size_spec.cr

@@ -0,0 +1,17 @@
+require "./spec_helper"
+require "./fixture/*"
+
+describe BinaryParser::ByteSize do
+  describe "#bytesize" do
+    it "calculate size in byte" do
+      size = sizeof(UInt32) * 2 + sizeof(UInt8)
+      parser = ByteSizeFixture.new
+
+      expect(parser.bytesize).to eq(size)
+      parser.str = "foo"
+      expect(parser.bytesize).to eq(size + 3)
+      parser.arr = [0u8, 1u8, 2u8]
+      expect(parser.bytesize).to eq(size + 3 + sizeof(UInt8) * 3)
+    end
+  end
+end

spec/fixture/byte_size.cr

@@ -0,0 +1,11 @@
+require "../../src/binary_parser"
+
+class ByteSizeFixture < BinaryParser
+  uint8 :foo
+  uint32 :bar
+  uint32 :size
+  string :str, { count: :size }
+  array :arr, { count: :size, type: UInt8 }
+  include BinaryParser::ByteSize
+end
+