Support querying event sequences via iterators or streams.

These filters are meant to be used with, respectively, `Iterator::filter_map` and `StreamExt::filter_map`. The two operations are conceptually the same - they pass an item from the underlying sequence to a function that returns an option, drops the values for which the function returns `None`, and yields the value inside of `Some` in the resulting sequence.

However, `Iterator::filter_map` takes a function from the iterator elements to `Option<T>`. `StreamExt::filter_map` takes a function from the iterator elements to _a `Future` whose output is `Option<T>`_. As such, you can't easily use functions designed for one use case, for the other. You need an adapter - conventionally, `futures::ready`, if you have a non-async function and need an async one.

This provides two sets of sequence filters:

* `crate::test::fixtures::event` contains functions which return `Option` directly, and which are intended for use with `Iterator::filter_map`.
* `crate::test::fixtures::event::stream` contains lifted versions that return a `Future`, and which are intended for use with `StreamExt::filter_map`.

The lifting is done purely manually. I spent a lot of time writing clever-er versions before deciding on this; those were fun to write, but hell to read and not meaningfully better, and this is test support code, so we want it to be dumb and obvious. Complexity for the sake of intellectual satisfaction is a huge antifeature in this context.

1 files changed, 14 insertions, 14 deletions

diff --git a/src/event/handlers/stream/test/channel.rs b/src/event/handlers/stream/test/channel.rs
index 187c3c3..2b87ce2 100644
--- a/src/event/handlers/stream/test/channel.rs
+++ b/src/event/handlers/stream/test/channel.rs
@@ -35,8 +35,8 @@ async fn creating() {
     // Verify channel created event
 
     events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::created)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::created)
         .filter(|event| future::ready(event.channel == channel))
         .next()
         .expect_some("channel created event is delivered")
@@ -74,8 +74,8 @@ async fn previously_created() {
     // Verify channel created event
 
     let _ = events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::created)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::created)
         .filter(|event| future::ready(event.channel == channel))
         .next()
         .expect_some("channel created event is delivered")
@@ -111,8 +111,8 @@ async fn expiring() {
 
     // Check for expiry event
     let _ = events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::deleted)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::deleted)
         .filter(|event| future::ready(event.id == channel.id))
         .next()
         .expect_some("a deleted channel event will be delivered")
@@ -148,8 +148,8 @@ async fn previously_expired() {
 
     // Check for expiry event
     let _ = events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::deleted)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::deleted)
         .filter(|event| future::ready(event.id == channel.id))
         .next()
         .expect_some("a deleted channel event will be delivered")
@@ -185,8 +185,8 @@ async fn deleting() {
 
     // Check for delete event
     let _ = events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::deleted)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::deleted)
         .filter(|event| future::ready(event.id == channel.id))
         .next()
         .expect_some("a deleted channel event will be delivered")
@@ -222,8 +222,8 @@ async fn previously_deleted() {
 
     // Check for expiry event
     let _ = events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::deleted)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::deleted)
         .filter(|event| future::ready(event.id == channel.id))
         .next()
         .expect_some("a deleted channel event will be delivered")
@@ -264,8 +264,8 @@ async fn previously_purged() {
 
     // Check for expiry event
     events
-        .filter_map(fixtures::event::channel)
-        .filter_map(fixtures::event::channel::deleted)
+        .filter_map(fixtures::event::stream::channel)
+        .filter_map(fixtures::event::stream::channel::deleted)
         .filter(|event| future::ready(event.id == channel.id))
         .next()
         .expect_wait("deleted channel events not delivered")