spec/zscan_spec.rb in zscan-1.0 vs spec/zscan_spec.rb in zscan-1.0.1

@@ -62,6 +62,35 @@
     assert_equal ' ', z.scan(/\s*(\#.*$\s*)*/)
     z.pos = 1
     assert_equal '', z.scan(/(?<=a)/)
     assert_equal nil, z.scan(/^/)
   end
+
+  it "stack doesn't underflow" do
+    @z.push
+    @z.pop
+    @z.pop
+    @z.pos = 3
+    @z.push
+    @z.pos = 4
+    @z.pop
+    assert_equal 3, @z.pos
+  end
+
+  it "#try restores pos" do
+    z = ZScan.new "hello"
+    return1 = z.try do
+      z.scan 'h'
+      z.scan 'e'
+    end
+    assert_equal 'e', return1
+    assert_equal 2, z.pos
+
+    return2 = z.try do
+      z.scan 'l'
+      z.scan 'l'
+      z.scan 'p' # fails
+    end
+    assert_equal nil, return2
+    assert_equal 2, z.pos
+  end
 end