diff --git a/src/fairing.rs b/src/fairing.rs
index f2bb393..66703d5 100644
--- a/src/fairing.rs
+++ b/src/fairing.rs
@@ -88,7 +88,6 @@ impl rocket::fairing::Fairing for Cors {
 
     fn on_request(&self, request: &mut Request, _: &rocket::Data) {
         // Build and merge CORS response
-        // Type annotation is for sanity check
         let cors_response = validate(self, request);
         if let Err(ref err) = cors_response {
             error_!("CORS Error: {}", err);
@@ -105,3 +104,78 @@ impl rocket::fairing::Fairing for Cors {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use rocket::Rocket;
+    use rocket::http::{Method, Status};
+    use rocket::local::Client;
+
+    use {Cors, AllOrSome};
+
+    const CORS_ROOT: &'static str = "/my_cors";
+
+    fn make_cors_options() -> Cors {
+        let (allowed_origins, failed_origins) =
+            AllOrSome::new_from_str_list(&["https://www.acme.com"]);
+        assert!(failed_origins.is_empty());
+
+        Cors {
+            allowed_origins: allowed_origins,
+            allowed_methods: vec![Method::Get].into_iter().map(From::from).collect(),
+            allowed_headers: AllOrSome::Some(
+                ["Authorization"]
+                    .into_iter()
+                    .map(|s| s.to_string().into())
+                    .collect(),
+            ),
+            allow_credentials: true,
+            fairing_route_base: CORS_ROOT.to_string(),
+
+            ..Default::default()
+        }
+    }
+
+    fn rocket(fairing: Cors) -> Rocket {
+        Rocket::ignite().attach(fairing)
+    }
+
+    #[test]
+    fn fairing_error_route_returns_passed_in_status() {
+        let client = Client::new(rocket(make_cors_options())).expect("to not fail");
+        let request = client.get(format!("{}/403", CORS_ROOT));
+        let response = request.dispatch();
+        assert_eq!(Status::Forbidden, response.status());
+    }
+
+    #[test]
+    fn fairing_error_route_returns_500_for_unknown_status() {
+        let client = Client::new(rocket(make_cors_options())).expect("to not fail");
+        let request = client.get(format!("{}/999", CORS_ROOT));
+        let response = request.dispatch();
+        assert_eq!(Status::InternalServerError, response.status());
+    }
+
+    #[test]
+    fn error_route_is_mounted_on_attach() {
+        let rocket = rocket(make_cors_options());
+
+        let expected_uri = format!("{}/<status>", CORS_ROOT);
+        let error_route = rocket.routes().find(|r| {
+            r.method == Method::Get && r.uri.as_str() == expected_uri
+        });
+        assert!(error_route.is_some());
+    }
+
+    #[test]
+    #[should_panic(expected = "launch fairing failure")]
+    fn options_are_validated_on_attach() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        options.send_wildcard = true;
+
+        let _ = rocket(options).launch();
+    }
+
+    // Rest of the things can only be tested in integration tests
+}
diff --git a/src/headers.rs b/src/headers.rs
index b85e730..71dfee7 100644
--- a/src/headers.rs
+++ b/src/headers.rs
@@ -144,7 +144,7 @@ impl<'a, 'r> FromRequest<'a, 'r> for AccessControlRequestMethod {
 ///
 /// You can use this as a rocket [Request Guard](https://rocket.rs/guide/requests/#request-guards)
 /// to ensure that the header is passed in correctly.
-#[derive(Debug)]
+#[derive(Eq, PartialEq, Debug)]
 pub struct AccessControlRequestHeaders(pub HeaderFieldNamesSet);
 
 /// Will never fail
@@ -184,7 +184,6 @@ impl<'a, 'r> FromRequest<'a, 'r> for AccessControlRequestHeaders {
 }
 
 #[cfg(test)]
-#[allow(unmounted_route)]
 mod tests {
     use std::str::FromStr;
 
diff --git a/src/lib.rs b/src/lib.rs
index 4b294df..6181ffd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -500,14 +500,17 @@ impl Cors {
         "/cors".to_string()
     }
 
-    /// Build a CORS `Guard` to an incoming request.
+    /// Validate a request and then return a CORS Response
     ///
-    /// You will usually not have to use this function but simply place a route argument for the
-    /// `Guard` type. This is useful if you want an even more ad-hoc based approach to respond to
+    /// You will usually not have to use this function but simply place a r
+    /// equest guard in the route argument for the `Guard` type.
+    ///
+    /// This is useful if you want an even more ad-hoc based approach to respond to
     /// CORS by using a `Cors` that is not in Rocket's managed state.
-    pub fn guard<'a, 'r>(&'a self, request: &'a Request<'r>) -> Result<Guard<'r>, Error> {
+    #[doc(hidden)] // Need to figure out a way to do this
+    pub fn validate_request<'a, 'r>(&'a self, request: &'a Request<'r>) -> Result<Response, Error> {
         let response = validate_and_build(self, request)?;
-        Ok(Guard::new(response))
+        Ok(response)
     }
 
     /// Validates if any of the settings are disallowed or incorrect
@@ -531,8 +534,11 @@ impl Cors {
 /// - `Access-Control-Allow-Methods`
 /// - `Access-Control-Allow-Headers`
 /// - `Vary`
+///
+/// You can get this struct by using `Cors::validate_request` in an ad-hoc manner.
+#[doc(hidden)]
 #[derive(Eq, PartialEq, Debug)]
-struct Response {
+pub struct Response {
     allow_origin: Option<AllOrSome<String>>,
     allow_methods: HashSet<Method>,
     allow_headers: HeaderFieldNamesSet,
@@ -705,8 +711,8 @@ impl Response {
 /// A [request guard](https://rocket.rs/guide/requests/#request-guards) to check CORS headers
 /// before a route is run. Will not execute the route if checks fail
 ///
-// In essence, this is just a wrapper around `Response` with a `'r` borrowed lifetime so users
-// don't have to keep specifying the lifetimes in their routes
+/// In essence, this is just a wrapper around `Response` with a `'r` borrowed lifetime so users
+/// don't have to keep specifying the lifetimes in their routes
 pub struct Guard<'r> {
     response: Response,
     marker: PhantomData<&'r Response>,
@@ -799,6 +805,7 @@ impl<'r, R: response::Responder<'r>> response::Responder<'r> for Responder<'r, R
 /// Result of CORS validation.
 ///
 /// The variants hold enough information to build a response to the validation result
+#[derive(Debug, Eq, PartialEq)]
 enum ValidationResult {
     /// Not a CORS request
     None,
@@ -1122,12 +1129,15 @@ fn actual_request_response(options: &Cors, origin: Origin) -> Response {
 }
 
 #[cfg(test)]
-#[allow(unmounted_route)]
 mod tests {
     use std::str::FromStr;
+
+    use rocket::local::Client;
+    use rocket::http::Header;
     use serde_json;
-    use http::Method;
+
     use super::*;
+    use http::Method;
 
     fn make_cors_options() -> Cors {
         let (allowed_origins, failed_origins) =
@@ -1141,16 +1151,34 @@ mod tests {
                 .map(From::from)
                 .collect(),
             allowed_headers: AllOrSome::Some(
-                ["Authorization"]
+                ["Authorization", "Accept"]
                     .into_iter()
                     .map(|s| s.to_string().into())
                     .collect(),
             ),
             allow_credentials: true,
+            expose_headers: ["Content-Type", "X-Custom"]
+                .into_iter()
+                .map(|s| s.to_string().into())
+                .collect(),
             ..Default::default()
         }
     }
 
+    fn make_invalid_options() -> Cors {
+        let mut cors = make_cors_options();
+        cors.allow_credentials = true;
+        cors.allowed_origins = AllOrSome::All;
+        cors.send_wildcard = true;
+        cors
+    }
+
+    /// Make a client with no routes for unit testing
+    fn make_client() -> Client {
+        let rocket = rocket::ignite();
+        Client::new(rocket).expect("valid rocket instance")
+    }
+
     // CORS options test
 
     #[test]
@@ -1161,10 +1189,7 @@ mod tests {
     #[test]
     #[should_panic(expected = "CredentialsWithWildcardOrigin")]
     fn cors_validates_illegal_allow_credentials() {
-        let mut cors = make_cors_options();
-        cors.allow_credentials = true;
-        cors.allowed_origins = AllOrSome::All;
-        cors.send_wildcard = true;
+        let cors = make_invalid_options();
 
         cors.validate().unwrap();
     }
@@ -1416,8 +1441,447 @@ mod tests {
         );
     }
 
-    // TODO: Preflight tests
-    // TODO: Actual requests tests
+    #[test]
+    fn preflight_validated_correctly() {
+        let options = make_cors_options();
+        let client = make_client();
 
-    // Origin all (wildcard + echoed with Vary). Origin Echo
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let result = validate(&options, request.inner()).expect("to not fail");
+        let expected_result = ValidationResult::Preflight {
+            origin: FromStr::from_str("https://www.acme.com").unwrap(),
+            // Checks that only a subset of allowed headers are returned
+            // -- i.e. whatever is requested for
+            headers: Some(FromStr::from_str("Authorization").unwrap()),
+        };
+
+        assert_eq!(expected_result, result);
+    }
+
+    #[test]
+    #[should_panic(expected = "CredentialsWithWildcardOrigin")]
+    fn preflight_validation_errors_on_invalid_options() {
+        let options = make_invalid_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    fn preflight_validation_allows_all_origin() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.example.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let result = validate(&options, request.inner()).expect("to not fail");
+        let expected_result = ValidationResult::Preflight {
+            origin: FromStr::from_str("https://www.example.com").unwrap(),
+            headers: Some(FromStr::from_str("Authorization").unwrap()),
+        };
+
+        assert_eq!(expected_result, result);
+    }
+
+    #[test]
+    #[should_panic(expected = "OriginNotAllowed")]
+    fn preflight_validation_errors_on_invalid_origin() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.example.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    #[should_panic(expected = "MissingRequestMethod")]
+    fn preflight_validation_errors_on_missing_request_method() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client.options("/").header(origin_header).header(
+            request_headers,
+        );
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    #[should_panic(expected = "MethodNotAllowed")]
+    fn preflight_validation_errors_on_disallowed_method() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Post,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    #[should_panic(expected = "HeadersNotAllowed")]
+    fn preflight_validation_errors_on_disallowed_headers() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(vec![
+            FromStr::from_str("Authorization").unwrap(),
+            FromStr::from_str("X-NOT-ALLOWED").unwrap(),
+        ]);
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    fn actual_request_validated_correctly() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let result = validate(&options, request.inner()).expect("to not fail");
+        let expected_result = ValidationResult::Request {
+            origin: FromStr::from_str("https://www.acme.com").unwrap(),
+        };
+
+        assert_eq!(expected_result, result);
+    }
+
+    #[test]
+    #[should_panic(expected = "CredentialsWithWildcardOrigin")]
+    fn actual_request_validation_errors_on_invalid_options() {
+        let options = make_invalid_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    fn actual_request_validation_allows_all_origin() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.example.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let result = validate(&options, request.inner()).expect("to not fail");
+        let expected_result = ValidationResult::Request {
+            origin: FromStr::from_str("https://www.example.com").unwrap(),
+        };
+
+        assert_eq!(expected_result, result);
+    }
+
+    #[test]
+    #[should_panic(expected = "OriginNotAllowed")]
+    fn actual_request_validation_errors_on_incorrect_origin() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.example.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let _ = validate(&options, request.inner()).unwrap();
+    }
+
+    #[test]
+    fn non_cors_request_return_empty_response() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let request = client.options("/");
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+        let expected_response = Response::new();
+        assert_eq!(expected_response, response);
+    }
+
+    #[test]
+    fn preflight_validated_and_built_correctly() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+
+        let expected_response = Response::new()
+            .origin("https://www.acme.com/", false)
+            .headers(&["Authorization"])
+            .methods(&options.allowed_methods)
+            .credentials(options.allow_credentials)
+            .max_age(options.max_age);
+
+        assert_eq!(expected_response, response);
+    }
+
+    /// Tests that when All origins are allowed and send_wildcard disabled, the vary header is set
+    /// in the response and the requested origin is echoed
+    #[test]
+    fn preflight_all_origins_with_vary() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        options.send_wildcard = false;
+
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+
+        let expected_response = Response::new()
+            .origin("https://www.acme.com/", true)
+            .headers(&["Authorization"])
+            .methods(&options.allowed_methods)
+            .credentials(options.allow_credentials)
+            .max_age(options.max_age);
+
+        assert_eq!(expected_response, response);
+    }
+
+    /// Tests that when All origins are allowed and send_wildcard enabled, the origin is set to "*"
+    #[test]
+    fn preflight_all_origins_with_wildcard() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        options.send_wildcard = true;
+        options.allow_credentials = false;
+
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let method_header = Header::from(hyper::header::AccessControlRequestMethod(
+            hyper::method::Method::Get,
+        ));
+        let request_headers = hyper::header::AccessControlRequestHeaders(
+            vec![FromStr::from_str("Authorization").unwrap()],
+        );
+        let request_headers = Header::from(request_headers);
+
+        let request = client
+            .options("/")
+            .header(origin_header)
+            .header(method_header)
+            .header(request_headers);
+
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+
+        let expected_response = Response::new()
+            .any()
+            .headers(&["Authorization"])
+            .methods(&options.allowed_methods)
+            .credentials(options.allow_credentials)
+            .max_age(options.max_age);
+
+        assert_eq!(expected_response, response);
+    }
+
+    #[test]
+    fn actual_request_validated_and_built_correctly() {
+        let options = make_cors_options();
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+        let expected_response = Response::new()
+            .origin("https://www.acme.com/", false)
+            .credentials(options.allow_credentials)
+            .exposed_headers(&["Content-Type", "X-Custom"]);
+
+        assert_eq!(expected_response, response);
+    }
+
+    #[test]
+    fn actual_request_all_origins_with_vary() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        options.send_wildcard = false;
+        options.allow_credentials = false;
+
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+        let expected_response = Response::new()
+            .origin("https://www.acme.com/", true)
+            .credentials(options.allow_credentials)
+            .exposed_headers(&["Content-Type", "X-Custom"]);
+
+        assert_eq!(expected_response, response);
+    }
+
+    #[test]
+    fn actual_request_all_origins_with_wildcard() {
+        let mut options = make_cors_options();
+        options.allowed_origins = AllOrSome::All;
+        options.send_wildcard = true;
+        options.allow_credentials = false;
+
+        let client = make_client();
+
+        let origin_header = Header::from(
+            hyper::header::Origin::from_str("https://www.acme.com").unwrap(),
+        );
+        let request = client.get("/").header(origin_header);
+
+        let response = validate_and_build(&options, request.inner()).expect("to not fail");
+        let expected_response = Response::new()
+            .any()
+            .credentials(options.allow_credentials)
+            .exposed_headers(&["Content-Type", "X-Custom"]);
+
+        assert_eq!(expected_response, response);
+    }
 }
diff --git a/tests/fairing.rs b/tests/fairing.rs
index 7518ee1..9d579f0 100644
--- a/tests/fairing.rs
+++ b/tests/fairing.rs
@@ -31,7 +31,7 @@ fn make_cors_options() -> Cors {
         allowed_origins: allowed_origins,
         allowed_methods: vec![Method::Get].into_iter().map(From::from).collect(),
         allowed_headers: AllOrSome::Some(
-            ["Authorization"]
+            ["Authorization", "Accept"]
                 .into_iter()
                 .map(|s| s.to_string().into())
                 .collect(),
diff --git a/tests/ad_hoc.rs b/tests/guard.rs
similarity index 98%
rename from tests/ad_hoc.rs
rename to tests/guard.rs
index 22cdfe1..091f09f 100644
--- a/tests/ad_hoc.rs
+++ b/tests/guard.rs
@@ -1,4 +1,4 @@
-//! This crate tests using rocket_cors using the "classic" ad-hoc per-route handling
+//! This crate tests using rocket_cors using the per-route handling with request guard
 
 #![feature(plugin, custom_derive)]
 #![plugin(rocket_codegen)]
@@ -68,7 +68,7 @@ fn make_cors_options() -> cors::Cors {
         allowed_origins: allowed_origins,
         allowed_methods: vec![Method::Get].into_iter().map(From::from).collect(),
         allowed_headers: cors::AllOrSome::Some(
-            ["Authorization"]
+            ["Authorization", "Accept"]
                 .into_iter()
                 .map(|s| s.to_string().into())
                 .collect(),