ci: add headless browser tests for wasm

Squashed the following commits by @TalDerei:

  * update wasm readme and add action workflow file
  * trigger workflow on pull-request
  * add assertion check to wasm unit test
  * modify path in ci workflow
  * attemp to pass CI
  * add wasm-pack binary to workflow
  * attempt to run in headless browser mode
  * add firefox execution environment

We struggled a bit in getting the test to pass CI, but it was as simple
as ensuring that lfs=true on the repo checkout.

Closes #3475.

.github/workflows/rust.yml

@@ -85,24 +85,24 @@ jobs:
       - name: Load rust cache
         uses: astriaorg/[email protected]
 
-      - name: build wasm32 target
-        run: cargo build --release --target wasm32-unknown-unknown
-        # TODO: consider failing on warnings here. A few dead-code
-        # warnings, leaving as-is because wasm is undergoing rapid dev
-        # in support of web extension.
-        working-directory: crates/wasm
-
       # Download prebuilt binary for wasm-pack; faster than `cargo install`.
       - uses: jetli/[email protected]
         with:
           version: 'latest'
 
-      # `wasm-pack build` will automatically compile to target wasm32-unknown-unknown,
-      # but we run it as a separate task to isolate potential failures in the build pipeline.
+      # Ensure that wasm crate builds cleanly. Is this superfluous, given `wasm-pack test` below?
       - name: run wasm-pack build
         run: wasm-pack build
         working-directory: crates/wasm
 
+      # Download firefox
+      - uses: browser-actions/setup-firefox@v1
+      - run: firefox --version
+
+      - name: Run headless browser tests
+        run: wasm-pack test --headless --firefox -- --test test_build --target wasm32-unknown-unknown --release --features "mock-database"
+        working-directory: crates/wasm
+
       # Always show the results of `cargo tree`, even if the tests failed, since that
       # output will be immediately useful in debugging.
       - name: display mio deps

crates/wasm/README.md

@@ -14,3 +14,15 @@ wasm-pack build
 ```
 
 Artifacts can be found in `pkg/`.
+
+## Testing
+The WASM crate incorporates a unit testing suite that leverages `wasm-bindgen-test` to simulate a sample spend transaction.
+For testing purposes, the suite mocks `indexDB` database calls in an interactive browser accessible at `http://127.0.0.1:8000`.
+
+```
+wasm-pack test --chrome -- --test test_build --target wasm32-unknown-unknown --release --features "mock-database"
+```
+
+The transaction outputs are accessible in the browser's developer console.
+
+The wasm browser tests are also run headlessly in Penumbra CI. Review the relevant GHA workflow file for specifics.

crates/wasm/tests/test_build.rs

@@ -24,7 +24,7 @@ mod tests {
     use penumbra_tct::{structure::Hash, Forgotten};
     use penumbra_transaction::{
         plan::{ActionPlan, TransactionPlan},
-        Action,
+        Action, Transaction,
     };
     use penumbra_wasm::{
         build::build_action,
@@ -478,7 +478,7 @@ mod tests {
         }
 
         // Deserialize actions.
-        let action_deserialized = serde_wasm_bindgen::to_value(&actions).unwrap();
+        let action_deserialized: JsValue = serde_wasm_bindgen::to_value(&actions).unwrap();
 
         // Execute parallel spend transaction and generate proof.
         let parallel_transaction = build_parallel(
@@ -499,5 +499,17 @@ mod tests {
         )
         .unwrap();
         console_log!("Serial transaction is: {:?}", serial_transaction);
+
+        // Deserialize transactions and stringify actions in the transaction body into JSON
+        let serial_result: Transaction =
+            serde_wasm_bindgen::from_value(serial_transaction).unwrap();
+        let parallel_result: Transaction =
+            serde_wasm_bindgen::from_value(parallel_transaction).unwrap();
+        let serial_json = serde_json::to_string(&serial_result.transaction_body.actions).unwrap();
+        let parallel_json =
+            serde_json::to_string(&parallel_result.transaction_body.actions).unwrap();
+
+        // Perform assertion check
+        assert_eq!(serial_json, parallel_json);
     }
 }