diff --git a/.github/codecov.yml b/.github/codecov.yml
index 6d4b076c..2af9c192 100644
--- a/.github/codecov.yml
+++ b/.github/codecov.yml
@@ -9,6 +9,5 @@ coverage:
         threshold: 1%
 
 ignore:
-  - "ffi"
   - "benches"
   - "tests"
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 64821c3a..682f8691 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -110,6 +110,8 @@ jobs:
   coverage:
     runs-on: ubuntu-latest
     steps:
+      - name: Install opencl
+        run: sudo apt-get install -y libpocl2 mesa-opencl-icd ocl-icd-opencl-dev
       - uses: actions/checkout@v3
       - name: Install stable
         uses: dtolnay/rust-toolchain@stable
@@ -117,11 +119,8 @@ jobs:
           components: llvm-tools-preview
       - name: cargo install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
-      - name: cargo generate-lockfile
-        if: hashFiles('Cargo.lock') == ''
-        run: cargo generate-lockfile
       - name: cargo llvm-cov
-        run: cargo llvm-cov --locked --all-features --lcov --output-path lcov.info
+        run: cargo llvm-cov --locked --all-features --lcov --output-path lcov.info --workspace --ignore-filename-regex "main.rs" -- --test-threads=1
       - name: Upload to codecov.io
         uses: codecov/codecov-action@v3
         with:
@@ -171,7 +170,7 @@ jobs:
             toolchain: stable
     steps:
       - if: matrix.os == 'ubuntu-20.04'
-        run: sudo apt-get install -y libpocl2 mesa-opencl-icd ocl-icd-opencl-dev
+        run: sudo apt-get install -y mesa-opencl-icd ocl-icd-opencl-dev
         name: Install opencl
       - if: matrix.os == 'windows-2019'
         name: Install opencl
diff --git a/ffi/src/log.rs b/ffi/src/log.rs
index de212449..11222c29 100644
--- a/ffi/src/log.rs
+++ b/ffi/src/log.rs
@@ -77,3 +77,60 @@ pub extern "C" fn set_logging_callback(
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use log::{Level, Log, Metadata, Record};
+
+    use super::ExternCLog;
+
+    #[test]
+    fn test_c_logger() {
+        extern "C" fn cb(record: &super::ExternCRecord) {
+            assert_eq!(record.level, Level::Info);
+            assert_eq!(
+                unsafe {
+                    std::str::from_utf8(std::slice::from_raw_parts(
+                        record.message.ptr as _,
+                        record.message.len,
+                    ))
+                },
+                Ok("Hello, world!")
+            );
+            assert_eq!(record.line, 77,);
+            assert_eq!(
+                unsafe {
+                    std::str::from_utf8(std::slice::from_raw_parts(
+                        record.file.ptr as _,
+                        record.file.len,
+                    ))
+                },
+                Ok("test.rs")
+            );
+            assert_eq!(
+                unsafe {
+                    std::str::from_utf8(std::slice::from_raw_parts(
+                        record.module_path.ptr as _,
+                        record.module_path.len,
+                    ))
+                },
+                Ok("test_module")
+            );
+        }
+
+        let logger = ExternCLog::new(Level::Info, cb);
+
+        assert!(logger.enabled(&Metadata::builder().level(Level::Info).build()));
+        assert!(!logger.enabled(&Metadata::builder().level(Level::Debug).build()));
+
+        logger.log(
+            &Record::builder()
+                .args(format_args!("Hello, world!"))
+                .level(Level::Info)
+                .file(Some("test.rs"))
+                .line(Some(77))
+                .module_path(Some("test_module"))
+                .build(),
+        );
+    }
+}