public void ContainsAndContainsKeyWork()
{
IDictionary <string, StringValues> headers = new HttpRequestHeaders();
var kv1 = new KeyValuePair <string, StringValues>("host", new[] { "localhost" });
var kv2 = new KeyValuePair <string, StringValues>("custom", new[] { "value" });
var kv3 = new KeyValuePair <string, StringValues>("Content-Length", new[] { "0" });
var kv1b = new KeyValuePair <string, StringValues>("host", new[] { "not-localhost" });
var kv2b = new KeyValuePair <string, StringValues>("custom", new[] { "not-value" });
var kv3b = new KeyValuePair <string, StringValues>("Content-Length", new[] { "1" });
Assert.False(headers.ContainsKey("host"));
Assert.False(headers.ContainsKey("custom"));
Assert.False(headers.ContainsKey("Content-Length"));
Assert.False(headers.Contains(kv1));
Assert.False(headers.Contains(kv2));
Assert.False(headers.Contains(kv3));
headers["host"] = kv1.Value;
Assert.True(headers.ContainsKey("host"));
Assert.False(headers.ContainsKey("custom"));
Assert.False(headers.ContainsKey("Content-Length"));
Assert.True(headers.Contains(kv1));
Assert.False(headers.Contains(kv2));
Assert.False(headers.Contains(kv3));
Assert.False(headers.Contains(kv1b));
Assert.False(headers.Contains(kv2b));
Assert.False(headers.Contains(kv3b));
headers["custom"] = kv2.Value;
Assert.True(headers.ContainsKey("host"));
Assert.True(headers.ContainsKey("custom"));
Assert.False(headers.ContainsKey("Content-Length"));
Assert.True(headers.Contains(kv1));
Assert.True(headers.Contains(kv2));
Assert.False(headers.Contains(kv3));
Assert.False(headers.Contains(kv1b));
Assert.False(headers.Contains(kv2b));
Assert.False(headers.Contains(kv3b));
headers["Content-Length"] = kv3.Value;
Assert.True(headers.ContainsKey("host"));
Assert.True(headers.ContainsKey("custom"));
Assert.True(headers.ContainsKey("Content-Length"));
Assert.True(headers.Contains(kv1));
Assert.True(headers.Contains(kv2));
Assert.True(headers.Contains(kv3));
Assert.False(headers.Contains(kv1b));
Assert.False(headers.Contains(kv2b));
Assert.False(headers.Contains(kv3b));
}