WIP: generate sample template contexts for testing

crates/core/src/storage/user.rs

@@ -69,6 +69,17 @@ impl SessionInfo {
         self.active = false;
         Ok(self)
     }
+
+    pub(crate) fn samples() -> Vec<Self> {
+        vec![SessionInfo {
+            id: 1,
+            user_id: 2,
+            username: "john".to_string(),
+            active: true,
+            created_at: Utc::now(),
+            last_authd_at: Some(Utc::now()),
+        }]
+    }
 }
 
 #[derive(Debug, Error)]

crates/core/src/templates/context.rs

@@ -15,7 +15,7 @@
 //! Contexts used in templates
 
 use oauth2_types::errors::OAuth2Error;
-use serde::Serialize;
+use serde::{ser::SerializeStruct, Serialize};
 use url::Url;
 
 use crate::{errors::ErroredForm, filters::CsrfToken, storage::SessionInfo};
@@ -51,15 +51,11 @@ pub trait TemplateContext {
             inner: self,
         }
     }
-}
 
-impl TemplateContext for EmptyContext {}
+    fn sample() -> Vec<Self>
-impl TemplateContext for IndexContext {}
+    where
-impl TemplateContext for LoginContext {}
+        Self: Sized;
-impl<T> TemplateContext for FormPostContext<T> {}
+}
-impl<T> TemplateContext for WithSession<T> {}
-impl<T> TemplateContext for WithOptionalSession<T> {}
-impl<T> TemplateContext for WithCsrf<T> {}
 
 /// Context with a CSRF token in it
 #[derive(Serialize)]
@@ -70,6 +66,21 @@ pub struct WithCsrf<T> {
     inner: T,
 }
 
+impl<T: TemplateContext> TemplateContext for WithCsrf<T> {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        T::sample()
+            .into_iter()
+            .map(|inner| WithCsrf {
+                csrf_token: "fake_csrf_token".into(),
+                inner,
+            })
+            .collect()
+    }
+}
+
 /// Context with a user session in it
 #[derive(Serialize)]
 pub struct WithSession<T> {
@@ -79,6 +90,23 @@ pub struct WithSession<T> {
     inner: T,
 }
 
+impl<T: TemplateContext> TemplateContext for WithSession<T> {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        SessionInfo::samples()
+            .into_iter()
+            .flat_map(|session| {
+                T::sample().into_iter().map(move |inner| WithSession {
+                    current_session: session.clone(),
+                    inner,
+                })
+            })
+            .collect()
+    }
+}
+
 /// Context with an optional user session in it
 #[derive(Serialize)]
 pub struct WithOptionalSession<T> {
@@ -88,10 +116,52 @@ pub struct WithOptionalSession<T> {
     inner: T,
 }
 
+impl<T: TemplateContext> TemplateContext for WithOptionalSession<T> {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        SessionInfo::samples()
+            .into_iter()
+            .map(Some) // Wrap all samples in an Option
+            .chain(std::iter::once(None)) // Add the "None" option
+            .flat_map(|session| {
+                T::sample()
+                    .into_iter()
+                    .map(move |inner| WithOptionalSession {
+                        current_session: session.clone(),
+                        inner,
+                    })
+            })
+            .collect()
+    }
+}
+
 /// An empty context used for composition
-#[derive(Serialize)]
 pub struct EmptyContext;
 
+impl Serialize for EmptyContext {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        let mut s = serializer.serialize_struct("EmptyContext", 0)?;
+        // FIXME: for some reason, serde seems to not like struct flattening with empty
+        // stuff
+        s.serialize_field("__UNUSED", &())?;
+        s.end()
+    }
+}
+
+impl TemplateContext for EmptyContext {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        vec![EmptyContext]
+    }
+}
+
 /// Context used by the `index.html` template
 #[derive(Serialize)]
 pub struct IndexContext {
@@ -105,6 +175,19 @@ impl IndexContext {
     }
 }
 
+impl TemplateContext for IndexContext {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        vec![Self {
+            discovery_url: "https://example.com/.well-known/openid-configuration"
+                .parse()
+                .unwrap(),
+        }]
+    }
+}
+
 #[derive(Serialize, Debug, Clone, Copy, Hash, PartialEq, Eq)]
 #[serde(rename_all = "kebab-case")]
 pub enum LoginFormField {
@@ -118,6 +201,18 @@ pub struct LoginContext {
     form: ErroredForm<LoginFormField>,
 }
 
+impl TemplateContext for LoginContext {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        // TODO: samples with errors
+        vec![LoginContext {
+            form: ErroredForm::default(),
+        }]
+    }
+}
+
 impl LoginContext {
     #[must_use]
     pub fn with_form_error(form: ErroredForm<LoginFormField>) -> Self {
@@ -140,6 +235,22 @@ pub struct FormPostContext<T> {
     params: T,
 }
 
+impl<T: TemplateContext> TemplateContext for FormPostContext<T> {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        let sample_params = T::sample();
+        sample_params
+            .into_iter()
+            .map(|params| FormPostContext {
+                redirect_uri: "https://example.com/callback".parse().unwrap(),
+                params,
+            })
+            .collect()
+    }
+}
+
 impl<T> FormPostContext<T> {
     pub fn new(redirect_uri: Url, params: T) -> Self {
         Self {
@@ -157,6 +268,22 @@ pub struct ErrorContext {
     details: Option<String>,
 }
 
+impl TemplateContext for ErrorContext {
+    fn sample() -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        vec![
+            Self::new()
+                .with_code("sample_error")
+                .with_description("A fancy description".into())
+                .with_details("Something happened".into()),
+            Self::new().with_code("another_error"),
+            Self::new(),
+        ]
+    }
+}
+
 impl ErrorContext {
     #[must_use]
     pub fn new() -> Self {

crates/core/src/templates/macros.rs

@@ -32,6 +32,10 @@ macro_rules! register_templates {
             extra = { $( $extra_template:expr ),* };
         )?
 
+        $(
+            generics = { $( $generic:ident = $sample:ty ),* };
+        )?
+
         $(
             // Match any attribute on the function, such as #[doc], #[allow(dead_code)], etc.
             $( #[ $attr:meta ] )*
@@ -72,6 +76,34 @@ macro_rules! register_templates {
                         .map_err(|source| TemplateError::Render { template: $template, source })
                 }
             )*
+
+            pub fn check_render(&self) -> Result<(), TemplateError> {
+                self.check_render_inner $( ::< $( $sample ),+ > )? ()
+            }
+
+            fn check_render_inner
+            $( < $( $generic ),+ > )?
+            (&self) -> Result<(), TemplateError>
+            $( where
+                $( $generic : TemplateContext + Serialize, )+
+            )?
+
+            {
+                $(
+                    {
+                        let samples: Vec< $param > = TemplateContext::sample();
+
+                        let name = $template;
+                        for sample in samples {
+                            ::tracing::info!(name, "Rendering template");
+                            self. $name (&sample)?;
+                        }
+                    }
+                )*
+
+
+                Ok(())
+            }
         }
     };
 }

crates/core/src/templates/mod.rs

@@ -167,6 +167,7 @@ impl Reject for TemplateError {}
 
 register_templates! {
     extra = { "base.html" };
+    generics = { T = EmptyContext };
 
     /// Render the login page
     pub fn render_login(WithCsrf<LoginContext>) { "login.html" }
@@ -186,3 +187,14 @@ register_templates! {
     /// Render the HTML error page
     pub fn render_error(ErrorContext) { "error.html" }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn check_all_templates() {
+        let templates = Templates::load(None, true).unwrap();
+        templates.check_render().unwrap();
+    }
+}