Add tests to HTTP::Accept::Encodings with nil and empty string

test/http/encodings.rb

@@ -52,6 +52,10 @@
 		expect(encodings[2].encoding).to be == "deflate"
 	end
 
+	it "should accept empty string" do
+		expect(HTTP::Accept::Encodings.parse("")).to be == []
+	end
+
 	it "should not accept invalid input" do
 		[
 			"gzip;f=1", "br;gzip",
@@ -60,6 +64,10 @@
 			expect{HTTP::Accept::Encodings.parse(text)}.to raise_exception(HTTP::Accept::ParseError)
 		end
 	end
+
+	it "should not accept nil input" do
+		expect{HTTP::Accept::Encodings.parse(nil)}.to raise_exception(TypeError)
+	end
 
 	describe "browser_preferred_content_codings" do
 		it "should parse a non-blank header" do