Add erb example of eval coverage issue.

examples/erb/template.erb

@@ -0,0 +1,5 @@
+<% if value %>
+	Hello <%= value %>
+<% else %>
+	Hello <%= default %>
+<% end %>

examples/erb/test.rb

@@ -0,0 +1,19 @@
+#!/usr/bin/env ruby
+
+require 'coverage'
+require 'erb'
+
+Coverage.start(lines: true, eval: true)
+
+def test(value = nil, default: "World", path: 'template.erb')
+	template = ERB.new(File.read(path))
+	template.location = path
+
+	template.result(binding)
+end
+
+# The order changes coverage, previous results are discarded.
+test("World")
+test
+
+puts Coverage.result