refactor(tests): Install color_eyre when running tests

Shows nicer error reports when a test fails.
Because the install hook needs to be called once per process, and
cargo runs tests in parallel in the same process, the install hook
needs to be protected by a OnceCell.

Inspired by https://github.com/yaahc/color-eyre/pull/118/files

crates/dyndns/src/db/logic.rs

@@ -312,6 +312,8 @@ mod tests {
 
     #[test]
     fn test_do_ops_with_db() -> Result<()> {
+        crate::logger::init_color_eyre();
+
         let maybe_db_path = None;
         let conn = &mut setup_db(maybe_db_path)?;
         let domain_record = create_domain_record(

crates/dyndns/src/domain_record_api/digital_ocean.rs

@@ -158,6 +158,8 @@ mod tests {
     fn test_basic() {
         use crate::updater::{get_record_to_update, should_update_domain_ip};
 
+        crate::logger::init_color_eyre();
+
         figment::Jail::expect_with(|jail| {
             jail.create_file(
                 "config.toml",

crates/dyndns/src/logger.rs

@@ -52,3 +52,13 @@ impl Drop for EyreSpanTraceWorkaroundGuard {
         std::env::set_var(RUST_SPANTRACE_KEY, "1");
     }
 }
+
+struct ColorEyreGuard(());
+static INIT_COLOR_EYRE: OnceCell<ColorEyreGuard> = OnceCell::new();
+
+pub fn init_color_eyre() {
+    INIT_COLOR_EYRE.get_or_init(|| {
+        color_eyre::install().expect("Failed to initialize color_eyre");
+        ColorEyreGuard(())
+    });
+}

crates/dyndns/src/web/routes.rs

@@ -119,6 +119,8 @@ mod tests {
 
     #[test]
     fn generate_open_api_schema() {
+        crate::logger::init_color_eyre();
+
         let (_, api) = get_pure_router_and_open_api();
 
         let mut buf = Vec::with_capacity(128);