Better state management in spec and add some tests for MangaDex::Queue

spec/mangadex_spec.cr

@@ -0,0 +1,40 @@
+require "./spec_helper"
+
+include MangaDex
+
+describe Queue do
+	it "creates DB at given path" do
+		with_queue do |queue, path|
+			File.exists?(path).should be_true
+		end
+	end
+
+	it "inserts multiple jobs" do
+		with_queue do |queue|
+			j1 = Job.new "1", "1", "title", "manga_title", JobStatus::Error,
+				Time.utc
+			j2 = Job.new "2", "2", "title", "manga_title", JobStatus::Completed,
+				Time.utc
+			j3 = Job.new "0", "0", "title", "manga_title", JobStatus::Pending,
+				Time.utc
+			count = queue.push [j1, j2, j3]
+			count.should eq 3
+		end
+	end
+
+	it "pops pending job" do
+		with_queue do |queue|
+			job = queue.pop
+			job.should_not be_nil
+			job.not_nil!.id.should eq "0"
+		end
+	end
+
+	it "cleans up" do
+		State.reset
+		with_queue do
+			true
+		end
+	end
+end
+