Add more specs

spec/payload_spec.cr

@@ -1,5 +1,19 @@
 require "./spec_helper"
 
+class NonPositionIO < ::IO
+  def initialize(@data : Bytes)
+  end
+
+  def read(slice : Bytes)
+    slice.size.times { |i| slice[i] = @data[i] }
+    slice.size
+  end
+
+  def write(slice : Bytes) : Nil
+    raise NotImplementedError.new("write")
+  end
+end
+
 describe MQTT::Protocol::Payload do
   it ".new(Bytes) returns a BytesPayload" do
     obj = MQTT::Protocol::Payload.new("foo".to_slice)
@@ -76,27 +90,51 @@ describe MQTT::Protocol::Payload do
   end
 
   describe "IOPayload" do
-    it "#to_slice should peek if possible" do
-      io = IO::Memory.new("foo".to_slice)
-      io.rewind
+    describe "#to_slice" do
+      it "should peek if possible" do
+        io = IO::Memory.new("foo".to_slice)
+        io.rewind
 
-      obj = MQTT::Protocol::IOPayload.new(io, 3)
-      data = obj.to_slice
+        obj = MQTT::Protocol::IOPayload.new(io, 3)
+        data = obj.to_slice
 
-      obj.@data.should be_nil
+        obj.@data.should be_nil
+      end
+
+      it "should copy data if peek isn't possible" do
+        io = NonPositionIO.new("foo".to_slice)
+
+        obj = MQTT::Protocol::IOPayload.new(io, 3)
+        data = obj.to_slice
+
+        obj.@data.should eq "foo".to_slice
+      end
     end
 
-    it "#to_io should not affect position" do
-      io = IO::Memory.new("foo".to_slice)
-      io.rewind
+    describe "#to_io" do
+      it "should not affect position if io support pos/pos=" do
+        io = IO::Memory.new("foo".to_slice)
+        io.rewind
+
+        obj = MQTT::Protocol::IOPayload.new(io, 3)
+
+        dst = IO::Memory.new
+        obj.to_io(dst)
+
+        obj.@data.should be_nil
+        obj.@io.pos.should eq 0
+      end
+
+      it "should copy data if io doesn't support pos/pos=" do
+        io = NonPositionIO.new("foo".to_slice)
 
-      obj = MQTT::Protocol::IOPayload.new(io, 3)
+        obj = MQTT::Protocol::IOPayload.new(io, 3)
 
-      dst = IO::Memory.new
-      obj.to_io(dst)
+        dst = IO::Memory.new
+        obj.to_io(dst)
 
-      obj.@data.should be_nil
-      obj.@io.pos.should eq(0)
+        obj.@data.should eq "foo".to_slice
+      end
     end
   end
 end