Add tests

Dockerfile

@@ -8,7 +8,7 @@ ARG FFMPEG_ST
 ARG FFMPEG_MT
 ENV INSTALL_DIR=/src/build
 ENV FFMPEG_VERSION=n5.1
-ENV X264_BRANCH=stable-wasm
+ENV X264_BRANCH=4-cores
 ENV CFLAGS="$CFLAGS $EXTRA_CFLAGS"
 ENV LDFLAGS="$LDFLAGS $CFLAGS $EXTRA_LDFLAGS"
 ENV EM_PKG_CONFIG_PATH=$EM_PKG_CONFIG_PATH:$INSTALL_DIR/lib/pkgconfig:/emsdk/upstream/emscripten/system/lib/pkgconfig
@@ -20,7 +20,7 @@ ENV FFMPEG_MT=$FFMPEG_MT
 FROM emsdk-base AS x264-builder
 ADD https://github.com/ffmpegwasm/x264.git#$X264_BRANCH /src
 COPY build/x264.sh /src/build.sh
-RUN bash /src/build.sh
+RUN bash -x /src/build.sh
 
 # Base ffmpeg image with dependencies and source code populated.
 FROM emsdk-base AS ffmpeg-base
@@ -33,17 +33,17 @@ COPY --from=x264-builder $INSTALL_DIR $INSTALL_DIR
 # Build ffmpeg
 FROM ffmpeg-base AS ffmpeg-builder
 COPY build/ffmpeg.sh /src/build.sh
-RUN bash /src/build.sh
+RUN bash -x /src/build.sh
 
 # Build ffmpeg.wasm
 FROM ffmpeg-builder AS ffmpeg-wasm-builder
 COPY src/bind /src/wasm/bind
 COPY src/fftools /src/wasm/fftools
-RUN mkdir -p /src/dist
 COPY build/ffmpeg-wasm.sh build.sh
-# FIXME: find a way to export both entry points in one command.
-RUN bash /src/build.sh -o dist/ffmpeg.cjs
-RUN bash /src/build.sh -sEXPORT_ES6 -o dist/ffmpeg.js
+RUN mkdir -p /src/dist/commonjs
+RUN bash -x /src/build.sh -o dist/commonjs/ffmpeg.js
+RUN mkdir -p /src/dist/esm
+RUN bash -x /src/build.sh -sEXPORT_ES6 -o dist/esm/ffmpeg.js
 
 # Export ffmpeg-core.wasm to dist/, use `docker buildx build -o . .` to get assets
 FROM scratch AS exportor