diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a7769ea5..8d1b4f7f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ macOS-13, macOS-14 ]
+        os: [ macOS-14, macOS-15 ]
     runs-on: ${{matrix.os}}
 
     steps:
@@ -45,7 +45,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ macOS-13, macOS-14 ]
+        os: [ macOS-14, macOS-15 ]
         sim: [ tvOS, watchOS ]
     runs-on: ${{matrix.os}}
 
diff --git a/dinghy-lib/src/android/mod.rs b/dinghy-lib/src/android/mod.rs
index 0b7fe398..65a9a1b8 100644
--- a/dinghy-lib/src/android/mod.rs
+++ b/dinghy-lib/src/android/mod.rs
@@ -214,7 +214,8 @@ fn ndk() -> Result<Option<path::PathBuf>> {
 
 fn ndk_version(ndk: &path::Path) -> Result<String> {
     let sources_prop_file = ndk.join("source.properties");
-    let props = fs::read_to_string(&sources_prop_file)?;
+    let props = fs::read_to_string(&sources_prop_file)
+        .with_context(|| format!("Reading prop file {sources_prop_file:?}"))?;
     let revision_line = props
         .split("\n")
         .find(|l| l.starts_with("Pkg.Revision"))
diff --git a/dinghy-lib/src/apple/device.rs b/dinghy-lib/src/apple/device.rs
index 7158ab39..9a8afebc 100644
--- a/dinghy-lib/src/apple/device.rs
+++ b/dinghy-lib/src/apple/device.rs
@@ -57,7 +57,12 @@ impl IosDevice {
     }
 
     fn is_pre_ios_17(&self) -> Result<bool> {
-        Ok(semver::VersionReq::parse(&self.os)?.comparators.get(0).ok_or_else(|| anyhow!("Invalid iOS version: {}", self.os))?.major < 17)
+        Ok(semver::VersionReq::parse(&self.os)?
+            .comparators
+            .get(0)
+            .ok_or_else(|| anyhow!("Invalid iOS version: {}", self.os))?
+            .major
+            < 17)
     }
 
     fn is_locked(&self) -> Result<bool> {
@@ -547,7 +552,14 @@ fn launch_app(dev: &AppleSimDevice, app_args: &[&str], _envs: &[&str]) -> Result
         .to_string_lossy()
         .into_owned();
     let stdout_param = &format!("--stdout={}", stdout);
-    let mut xcrun_args: Vec<&str> = vec!["simctl", "launch", "-w", stdout_param, &dev.id, "Dinghy"];
+    let mut xcrun_args: Vec<&str> = vec![
+        "simctl",
+        "launch",
+        "--wait-for-debugger",
+        stdout_param,
+        &dev.id,
+        "Dinghy",
+    ];
     xcrun_args.extend(app_args);
     debug!("Launching app via xcrun using args: {:?}", xcrun_args);
     let launch_output = process::Command::new("xcrun")
@@ -572,7 +584,8 @@ fn launch_app(dev: &AppleSimDevice, app_args: &[&str], _envs: &[&str]) -> Result
         .arg("-s")
         .arg(lldb_script_filename)
         .output()?;
-    let test_contents = std::fs::read_to_string(stdout)?;
+    let test_contents = std::fs::read_to_string(&stdout)
+        .with_context(|| format!("Reading llvm stdout from {stdout}"))?;
     println!("{}", test_contents);
 
     let output: String = String::from_utf8_lossy(&output.stdout).to_string();
diff --git a/dinghy-lib/src/apple/mod.rs b/dinghy-lib/src/apple/mod.rs
index 2b5749d8..22359c12 100644
--- a/dinghy-lib/src/apple/mod.rs
+++ b/dinghy-lib/src/apple/mod.rs
@@ -19,11 +19,13 @@ pub struct SignatureSettings {
     pub file: String,
     pub entitlements: String,
     pub name: String,
+    #[allow(dead_code)]
     pub profile: String,
 }
 
 #[derive(Debug, Clone)]
 pub struct SigningIdentity {
+    #[allow(dead_code)]
     pub id: String,
     pub name: String,
     pub team: String,
@@ -274,7 +276,9 @@ fn devices_from_devicectl(devices: &mut HashMap<String, IosDevice>) -> Result<()
     if !devicectl.status.success() {
         bail!("xcrun command failed. Please check that \"xcrun devicectl list devices\" works.\n{devicectl:?}");
     }
-    for device in json::parse(&std::fs::read_to_string(tmpjson)?)?["result"]["devices"].members() {
+    let txt = std::fs::read_to_string(&tmpjson)
+        .with_context(|| format!("Reading devicectl json output {tmpjson:?}"))?;
+    for device in json::parse(&txt)?["result"]["devices"].members() {
         let Some(udid) = device["hardwareProperties"]["udid"]
             .as_str()
             .map(|s| s.to_string())
diff --git a/dinghy-lib/src/config.rs b/dinghy-lib/src/config.rs
index 619598eb..5820aaed 100644
--- a/dinghy-lib/src/config.rs
+++ b/dinghy-lib/src/config.rs
@@ -2,9 +2,8 @@ use itertools::Itertools;
 use serde::de;
 use serde::{Deserialize, Serialize};
 use std::fmt;
-use std::io::Read;
 use std::result;
-use std::{collections, fs, path};
+use std::{collections, path};
 
 use crate::errors::*;
 
@@ -185,10 +184,9 @@ impl Configuration {
 }
 
 fn read_config_file<P: AsRef<path::Path>>(file: P) -> Result<ConfigurationFileContent> {
-    let mut data = String::new();
-    let mut fd = fs::File::open(file)?;
-    fd.read_to_string(&mut data)?;
-    Ok(::toml::from_str(&data)?)
+    let file = file.as_ref();
+    let data = std::fs::read_to_string(file).with_context(|| format!("Reading {file:?}"))?;
+    Ok(toml::from_str(&data)?)
 }
 
 pub fn dinghy_config<P: AsRef<path::Path>>(dir: P) -> Result<Configuration> {