diff --git a/.github/workflows/host-tests.yml b/.github/workflows/host-tests.yml
index b336146..9004f21 100644
--- a/.github/workflows/host-tests.yml
+++ b/.github/workflows/host-tests.yml
@@ -2,7 +2,9 @@ name: Tests
 
 on:
   push:
-    branches: [main]
+    branches:
+      - main
+      - feature/observable-callback-coverage
   pull_request:
     branches: [main]
 
@@ -22,6 +24,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
+        with:
+          repository: Flowduino/ESPressio-Observable
+          ref: 3.0.1
+          path: deps/ESPressio-Observable
       - name: Install PlatformIO
         run: pip install platformio
       - name: Compile BasicSecurePayload
@@ -29,12 +36,14 @@ jobs:
           pio ci examples/BasicSecurePayload/BasicSecurePayload.ino
           --board esp32dev
           --lib .
+          --lib deps/ESPressio-Observable
           --project-option="build_flags=-std=gnu++17"
-          --project-option="build_unflags=-std=gnu++11"
+          --project-option="build_unflags=-std=gnu++11 -fno-rtti"
       - name: Compile MbedTLSAlgorithms
         run: >-
           pio ci examples/MbedTLSAlgorithms/MbedTLSAlgorithms.ino
           --board esp32dev
           --lib .
+          --lib deps/ESPressio-Observable
           --project-option="build_flags=-std=gnu++17"
-          --project-option="build_unflags=-std=gnu++11"
+          --project-option="build_unflags=-std=gnu++11 -fno-rtti"
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 0131149..1c72b36 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -11,7 +11,10 @@ FetchContent_Declare(
     GIT_TAG 3.0.1
     GIT_SHALLOW TRUE
 )
-FetchContent_MakeAvailable(ESPressioObservable)
+FetchContent_GetProperties(ESPressioObservable)
+if(NOT espressioobservable_POPULATED)
+    FetchContent_Populate(ESPressioObservable)
+endif()
 set(ESPRESSIO_OBSERVABLE_INCLUDE ${espressioobservable_SOURCE_DIR}/src)
 
 add_executable(Security test_security.cpp)