diff --git a/.github/actions/iamf-tools-builder/action.yml b/.github/actions/iamf-tools-builder/action.yml
new file mode 100644
index 00000000..7aa7218c
--- /dev/null
+++ b/.github/actions/iamf-tools-builder/action.yml
@@ -0,0 +1,10 @@
+name: iamf-tools-builder
+
+description: Run unit tests for IAMF Tools.
+
+runs:
+  using: composite
+  steps:
+    - shell: bash
+      run: |
+        bazelisk -c opt test iamf/...
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 00000000..6969021b
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,15 @@
+name: build
+
+on: [push, pull_request]
+
+jobs:
+  linux-amd64:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v2
+      - name: Build
+        uses: ./.github/actions/iamf-tools-builder
+        with:
+          platform: linux
+          architecture: amd64
diff --git a/external/libexpat.BUILD b/external/libexpat.BUILD
index 19baa80e..46ed71c5 100644
--- a/external/libexpat.BUILD
+++ b/external/libexpat.BUILD
@@ -30,6 +30,7 @@ cc_library(
     copts = ["-w"],
     defines = [
         "XML_STATIC",
+        "XML_GE",
     ],
     # Internally `libexpat` does not qualify any headers.
     includes = [
diff --git a/iamf/cli/adm_to_user_metadata/adm/xml_to_adm.cc b/iamf/cli/adm_to_user_metadata/adm/xml_to_adm.cc
index 75d7e62b..f3339b4b 100644
--- a/iamf/cli/adm_to_user_metadata/adm/xml_to_adm.cc
+++ b/iamf/cli/adm_to_user_metadata/adm/xml_to_adm.cc
@@ -189,13 +189,13 @@ bool IsUserMetadataDefined(absl::string_view xxxx_substring) {
 bool IsLoudspeakerLayoutValid(absl::string_view xxxx_substring) {
   static const absl::NoDestructor<absl::flat_hash_set<std::string>>
       kValidLoudspeakerLayouts({
-          "0001",  // Mono
-          "0002",  // Stereo
-          "0003",  // 5.1
-          "0004",  // 5.1.2
-          "0005",  // 5.1.4
-          "000f",  // 7.1
-          "0017",  // 7.1.4
+          {"0001"},  // Mono
+          {"0002"},  // Stereo
+          {"0003"},  // 5.1
+          {"0004"},  // 5.1.2
+          {"0005"},  // 5.1.4
+          {"000f"},  // 7.1
+          {"0017"},  // 7.1.4
       });
   return kValidLoudspeakerLayouts->contains(xxxx_substring);
 }
@@ -205,9 +205,9 @@ bool IsLoudspeakerLayoutValid(absl::string_view xxxx_substring) {
 bool IsHoaLayoutValid(absl::string_view xxxx_substring) {
   static const absl::NoDestructor<absl::flat_hash_set<std::string>>
       kValidHoaLayouts({
-          "0001",  // First-order ambisonics.
-          "0002",  // Second-order ambisonics.
-          "0003",  // Third-order ambisonics.
+          {"0001"},  // First-order ambisonics.
+          {"0002"},  // Second-order ambisonics.
+          {"0003"},  // Third-order ambisonics.
       });
   return kValidHoaLayouts->contains(xxxx_substring);
 }