add some reducer test coverage

test/sprocket/internal/reducer_test.gleam

@@ -1,4 +1,5 @@
 import sprocket/internal/reducer
+import sprocket/test_helpers
 
 type Model =
   Int
@@ -21,7 +22,7 @@ fn update(model, msg) -> #(Model, List(reducer.Cmd(Msg))) {
   }
 }
 
-pub fn reducer_should_dispatch() {
+pub fn reducer_should_dispatch_test() {
   let assert Ok(reducer_actor) = reducer.start(init(0), update, fn(_) { Nil })
 
   reducer.dispatch(reducer_actor, Increment)
@@ -41,4 +42,84 @@ pub fn reducer_should_dispatch() {
   let state = reducer.get_state(reducer_actor)
 
   let assert True = state == 0
+
+  reducer.shutdown(reducer_actor)
+}
+
+fn init_with_commands(value, cmds) -> #(Model, List(reducer.Cmd(Msg))) {
+  #(value, cmds)
+}
+
+fn increment_cmd() -> reducer.Cmd(Msg) {
+  fn(dispatch) { dispatch(Increment) }
+}
+
+pub fn reducer_should_process_initial_cmd_test() {
+  let assert Ok(reducer_actor) =
+    reducer.start(init_with_commands(0, [increment_cmd()]), update, fn(_) {
+      Nil
+    })
+
+  let state = reducer.get_state(reducer_actor)
+
+  let assert True = state == 0
+
+  reducer.process_commands(reducer_actor)
+
+  test_helpers.wait_until(
+    fn() {
+      let state = reducer.get_state(reducer_actor)
+
+      state == 1
+    },
+    1000,
+  )
+
+  let state = reducer.get_state(reducer_actor)
+
+  let assert True = state == 1
+
+  reducer.dispatch(reducer_actor, Reset)
+
+  let state = reducer.get_state(reducer_actor)
+
+  let assert True = state == 0
+
+  reducer.shutdown(reducer_actor)
+}
+
+pub fn reducer_should_process_multiple_cmds_test() {
+  let assert Ok(reducer_actor) =
+    reducer.start(
+      init_with_commands(0, [increment_cmd(), increment_cmd(), increment_cmd()]),
+      update,
+      fn(_) { Nil },
+    )
+
+  let state = reducer.get_state(reducer_actor)
+
+  let assert True = state == 0
+
+  reducer.process_commands(reducer_actor)
+
+  test_helpers.wait_until(
+    fn() {
+      let state = reducer.get_state(reducer_actor)
+
+      state == 3
+    },
+    1000,
+  )
+
+  let state = reducer.get_state(reducer_actor)
+
+  let assert True = state == 3
+
+  reducer.dispatch(reducer_actor, Reset)
+
+  let state = reducer.get_state(reducer_actor)
+
+  let assert True = state == 0
+
+  reducer.shutdown(reducer_actor)
 }