diff --git a/lib/tests/blargg.rs b/lib/tests/blargg.rs
index 10bf0b4..5e4ce88 100644
--- a/lib/tests/blargg.rs
+++ b/lib/tests/blargg.rs
@@ -6,14 +6,14 @@ use gb_emu_lib::connect::{EmulatorCoreTrait, RomFile};
 mod common;
 
 #[test]
-fn cpu_instrs() -> Result<(), String> {
+fn cpu_instrs() -> anyhow::Result<()> {
     run_blargg_test("cpu_instrs\n\n01:ok  02:ok  03:ok  04:ok  05:ok  06:ok  07:ok  08:ok  09:ok  10:ok  11:ok  \n\nPassed all tests", include_bytes!(
         "../../test-roms/blargg/cpu_instrs/cpu_instrs.gb"
     ),None)
 }
 
 #[test]
-fn instr_timing() -> Result<(), String> {
+fn instr_timing() -> anyhow::Result<()> {
     run_blargg_test(
         "instr_timing\n\n\nPassed",
         include_bytes!("../../test-roms/blargg/instr_timing/instr_timing.gb"),
@@ -22,7 +22,7 @@ fn instr_timing() -> Result<(), String> {
 }
 
 #[test]
-fn mem_timing() -> Result<(), String> {
+fn mem_timing() -> anyhow::Result<()> {
     run_blargg_test(
         "mem_timing\n\n\nPassed",
         include_bytes!("../../test-roms/blargg/mem_timing/mem_timing.gb"),
@@ -30,11 +30,17 @@ fn mem_timing() -> Result<(), String> {
     )
 }
 
+#[derive(Debug, thiserror::Error)]
+enum TestError {
+    #[error("Timeout")]
+    Timeout(String),
+}
+
 fn run_blargg_test<const N: usize>(
     correct_output: &str,
     rom: &[u8; N],
     extra_end: Option<Vec<&str>>,
-) -> Result<(), String> {
+) -> anyhow::Result<()> {
     let mut emu = emulator_setup(RomFile::Raw(rom.to_vec()))?;
 
     let mut end_strings = extra_end.unwrap_or_default();
@@ -54,7 +60,7 @@ fn run_blargg_test<const N: usize>(
             }
         }
         if began.elapsed() > timeout {
-            return Err(format!("Test timed out: output was {chars}"));
+            return Err(TestError::Timeout(format!("Test timed out: output was {chars}")).into());
         }
     }
 
diff --git a/lib/tests/common/mod.rs b/lib/tests/common/mod.rs
index a0b1925..90b6534 100644
--- a/lib/tests/common/mod.rs
+++ b/lib/tests/common/mod.rs
@@ -13,11 +13,9 @@ pub struct TestEmulator {
     pub serial_rx: Receiver<u8>,
 }
 
-pub fn emulator_setup(rom_file: RomFile) -> Result<TestEmulator, String> {
+pub fn emulator_setup(rom_file: RomFile) -> anyhow::Result<TestEmulator> {
     let (sender, receiver) = channel::<EmulatorMessage<[u8; 4]>>();
-    let rom = rom_file
-        .load(gb_emu_lib::connect::SramType::None)
-        .map_err(|_e| String::from("Error reading ROM: {_e:?}"))?;
+    let rom = rom_file.load(gb_emu_lib::connect::SramType::None)?;
     let (audio_output, audio_rx) = AudioOutput::new(
         48000.,
         1,
@@ -40,10 +38,8 @@ pub fn emulator_setup(rom_file: RomFile) -> Result<TestEmulator, String> {
             include_bytes!("../../../sameboy-bootroms/dmg_boot.bin").to_vec(),
         )));
 
-    let core = EmulatorCore::init(true, receiver, options);
-    sender
-        .send(EmulatorMessage::Start)
-        .map_err(|_e| String::from("Error sending message: {_e:?}"))?;
+    let core = EmulatorCore::init(true, receiver, options)?;
+    sender.send(EmulatorMessage::Start)?;
     Ok(TestEmulator {
         core,
         _sender: sender,