diff --git a/docker/Dockerfile.alpine b/docker/Dockerfile.alpine
index f09933c..92b2789 100644
--- a/docker/Dockerfile.alpine
+++ b/docker/Dockerfile.alpine
@@ -8,7 +8,7 @@
 #       No SELinux. Busybox's tools may differ from the upstream shadow-utils.
 
 # Pinned: see the note in Dockerfile.debian.
-FROM rust:1.98-alpine3.23
+FROM rust:1.99-alpine3.23
 
 RUN apk add --no-cache \
     musl-dev \
diff --git a/docker/Dockerfile.debian b/docker/Dockerfile.debian
index ec8d934..3a7870b 100644
--- a/docker/Dockerfile.debian
+++ b/docker/Dockerfile.debian
@@ -8,7 +8,7 @@
 
 # Pinned: an unpinned tag lands a new toolchain on main with no PR signal,
 # and clippy gains lints between releases. Renovate proposes the bump.
-FROM rust:1.98-trixie
+FROM rust:1.99-trixie
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     libpam0g-dev \
diff --git a/docker/Dockerfile.e2e b/docker/Dockerfile.e2e
index 497f9c0..440f744 100644
--- a/docker/Dockerfile.e2e
+++ b/docker/Dockerfile.e2e
@@ -10,7 +10,7 @@
 
 # ── Stage 1: build shadow-rs ────────────────────────────────────────
 # Pinned: see the note in Dockerfile.debian.
-FROM rust:1.98-trixie AS builder
+FROM rust:1.99-trixie AS builder
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     libpam0g-dev \
diff --git a/docs/PLATFORM-SUPPORT.md b/docs/PLATFORM-SUPPORT.md
index 41d309d..af6fd01 100644
--- a/docs/PLATFORM-SUPPORT.md
+++ b/docs/PLATFORM-SUPPORT.md
@@ -47,8 +47,8 @@ CI runs the full suite on three images:
 
 | Image | Base | libc | PAM | SELinux |
 |---|---|---|---|---|
-| `debian` | `rust:1.98-trixie` | glibc | Linux-PAM | headers |
-| `alpine` | `rust:1.98-alpine3.23` | musl (dynamic) | Linux-PAM | none |
+| `debian` | `rust:1.99-trixie` | glibc | Linux-PAM | headers |
+| `alpine` | `rust:1.99-alpine3.23` | musl (dynamic) | Linux-PAM | none |
 | `fedora` | `fedora:44` | glibc | Linux-PAM | enforcing |
 
 The base images are pinned. An unpinned tag lands a new toolchain on `main`
diff --git a/src/shadow-core/src/group.rs b/src/shadow-core/src/group.rs
index 78c588a..5418645 100644
--- a/src/shadow-core/src/group.rs
+++ b/src/shadow-core/src/group.rs
@@ -146,7 +146,7 @@ mod tests {
         assert_eq!(entry.name, "root");
         assert_eq!(entry.passwd, "x");
         assert_eq!(entry.gid, 0);
-        assert!(entry.members.is_empty());
+        assert!(entry.members.is_empty(), "{:?}", entry.members);
     }
 
     #[test]
@@ -225,7 +225,7 @@ mod tests {
         let path = dir.path().join("group");
         std::fs::write(&path, "").unwrap();
         let entries = read_group_file(&path).unwrap();
-        assert!(entries.is_empty());
+        assert!(entries.is_empty(), "{entries:?}");
     }
 
     use proptest::prelude::*;
diff --git a/src/shadow-core/src/gshadow.rs b/src/shadow-core/src/gshadow.rs
index a50c4c9..4905715 100644
--- a/src/shadow-core/src/gshadow.rs
+++ b/src/shadow-core/src/gshadow.rs
@@ -155,8 +155,8 @@ mod tests {
         let entry: GshadowEntry = "root:*::".parse().unwrap();
         assert_eq!(entry.name, "root");
         assert_eq!(entry.passwd, "*");
-        assert!(entry.admins.is_empty());
-        assert!(entry.members.is_empty());
+        assert!(entry.admins.is_empty(), "{:?}", entry.admins);
+        assert!(entry.members.is_empty(), "{:?}", entry.members);
     }
 
     #[test]
@@ -172,13 +172,13 @@ mod tests {
     fn test_parse_admins_only() {
         let entry: GshadowEntry = "wheel:!:root:".parse().unwrap();
         assert_eq!(entry.admins, vec!["root"]);
-        assert!(entry.members.is_empty());
+        assert!(entry.members.is_empty(), "{:?}", entry.members);
     }
 
     #[test]
     fn test_parse_members_only() {
         let entry: GshadowEntry = "docker:!::deploy,ci".parse().unwrap();
-        assert!(entry.admins.is_empty());
+        assert!(entry.admins.is_empty(), "{:?}", entry.admins);
         assert_eq!(entry.members, vec!["deploy", "ci"]);
     }
 
@@ -239,7 +239,7 @@ mod tests {
         let path = dir.path().join("gshadow");
         std::fs::write(&path, "").unwrap();
         let entries = read_gshadow_file(&path).unwrap();
-        assert!(entries.is_empty());
+        assert!(entries.is_empty(), "{entries:?}");
     }
 
     #[test]
diff --git a/src/shadow-core/src/os_error.rs b/src/shadow-core/src/os_error.rs
index 17e290c..11b6da3 100644
--- a/src/shadow-core/src/os_error.rs
+++ b/src/shadow-core/src/os_error.rs
@@ -34,7 +34,7 @@ mod tests {
         // Non-empty, and the bare OS text — not Rust's "... (os error 13)"
         // rendering (the regression that suffix-stripping prevents). We assert
         // the shape, not the exact wording, since libc may localize it.
-        assert!(!msg.is_empty());
+        assert!(!msg.is_empty(), "{msg:?}");
         assert!(!msg.contains("(os error"), "got: {msg:?}");
     }
 }
diff --git a/src/shadow-core/src/passwd.rs b/src/shadow-core/src/passwd.rs
index 62c1b20..1332a3b 100644
--- a/src/shadow-core/src/passwd.rs
+++ b/src/shadow-core/src/passwd.rs
@@ -359,7 +359,7 @@ mod tests {
         let path = dir.path().join("passwd");
         std::fs::write(&path, "").unwrap();
         let entries = read_passwd_file(&path).unwrap();
-        assert!(entries.is_empty());
+        assert!(entries.is_empty(), "{entries:?}");
     }
 
     // -------------------------------------------------------------------
diff --git a/src/shadow-core/src/shadow.rs b/src/shadow-core/src/shadow.rs
index a3b5dfe..e8a5996 100644
--- a/src/shadow-core/src/shadow.rs
+++ b/src/shadow-core/src/shadow.rs
@@ -565,7 +565,7 @@ mod tests {
         let path = dir.path().join("shadow");
         std::fs::write(&path, "").unwrap();
         let entries = read_shadow_file(&path).unwrap();
-        assert!(entries.is_empty());
+        assert!(entries.is_empty(), "{entries:?}");
     }
 
     // -------------------------------------------------------------------
diff --git a/src/shadow-core/src/subid.rs b/src/shadow-core/src/subid.rs
index 3a4cf09..12b6a3b 100644
--- a/src/shadow-core/src/subid.rs
+++ b/src/shadow-core/src/subid.rs
@@ -203,7 +203,7 @@ mod tests {
         let path = dir.path().join("subuid");
         std::fs::write(&path, "").unwrap();
         let entries = read_subid_file(&path).unwrap();
-        assert!(entries.is_empty());
+        assert!(entries.is_empty(), "{entries:?}");
     }
 
     #[test]
diff --git a/src/uu/chgpasswd/src/chgpasswd.rs b/src/uu/chgpasswd/src/chgpasswd.rs
index fbce623..2194059 100644
--- a/src/uu/chgpasswd/src/chgpasswd.rs
+++ b/src/uu/chgpasswd/src/chgpasswd.rs
@@ -604,7 +604,7 @@ mod tests {
         assert_eq!(entries[0].passwd, "$6$new");
         // The new line inherits the membership /etc/group already records.
         assert_eq!(entries[0].members, members);
-        assert!(entries[0].admins.is_empty());
+        assert!(entries[0].admins.is_empty(), "{:?}", entries[0].admins);
     }
 
     // -----------------------------------------------------------------------
diff --git a/src/uu/chsh/src/chsh.rs b/src/uu/chsh/src/chsh.rs
index f1b25bd..6e41429 100644
--- a/src/uu/chsh/src/chsh.rs
+++ b/src/uu/chsh/src/chsh.rs
@@ -428,7 +428,7 @@ mod tests {
         let dir = tempfile::tempdir().expect("tempdir");
         let path = dir.path().join("nonexistent");
         let shells = read_shells(&path).expect("read_shells");
-        assert!(shells.is_empty());
+        assert!(shells.is_empty(), "{shells:?}");
     }
 
     #[test]
@@ -437,7 +437,7 @@ mod tests {
         let path = dir.path().join("shells");
         std::fs::write(&path, "").expect("write");
         let shells = read_shells(&path).expect("read_shells");
-        assert!(shells.is_empty());
+        assert!(shells.is_empty(), "{shells:?}");
     }
 
     // -----------------------------------------------------------------------
diff --git a/src/uu/gpasswd/src/gpasswd.rs b/src/uu/gpasswd/src/gpasswd.rs
index da9a8f2..36c7de1 100644
--- a/src/uu/gpasswd/src/gpasswd.rs
+++ b/src/uu/gpasswd/src/gpasswd.rs
@@ -689,8 +689,12 @@ mod tests {
             parse_user_list("a, b ,c"),
             vec!["a".to_string(), "b".to_string(), "c".to_string()]
         );
-        assert!(parse_user_list("").is_empty());
-        assert!(parse_user_list(",,").is_empty());
+        assert!(parse_user_list("").is_empty(), "{:?}", parse_user_list(""));
+        assert!(
+            parse_user_list(",,").is_empty(),
+            "{:?}",
+            parse_user_list(",,")
+        );
     }
 
     #[test]
diff --git a/src/uu/login/src/login.rs b/src/uu/login/src/login.rs
index bfd7a6a..8934549 100644
--- a/src/uu/login/src/login.rs
+++ b/src/uu/login/src/login.rs
@@ -852,7 +852,7 @@ mod tests {
         assert_eq!(c.tty_perm, 0o600);
         assert_eq!(c.tty_group, "tty");
         assert!(c.default_home);
-        assert!(c.motd_files.is_empty());
+        assert!(c.motd_files.is_empty(), "{:?}", c.motd_files);
 
         let c = Config::from_defs(&defs(
             "LOGIN_RETRIES 5\nLOGIN_TIMEOUT 0\nTTYPERM 0620\nDEFAULT_HOME no\nMOTD_FILE /etc/motd:/run/motd\nLOGIN_PLAIN_PROMPT yes\nFAIL_DELAY 4\n",
diff --git a/src/uu/newusers/src/newusers.rs b/src/uu/newusers/src/newusers.rs
index ce85c19..00876ed 100644
--- a/src/uu/newusers/src/newusers.rs
+++ b/src/uu/newusers/src/newusers.rs
@@ -625,9 +625,9 @@ mod tests {
     fn test_all_optional_fields_may_be_empty() {
         let line = parse_line("alice:pw:::::", 1).expect("parses");
         assert_eq!(line.name, "alice");
-        assert!(line.uid.is_empty());
-        assert!(line.gid.is_empty());
-        assert!(line.home.is_empty());
+        assert!(line.uid.is_empty(), "{:?}", line.uid);
+        assert!(line.gid.is_empty(), "{:?}", line.gid);
+        assert!(line.home.is_empty(), "{:?}", line.home);
     }
 
     fn line(spec: &str) -> Line {
diff --git a/src/uu/pwconv/src/pwconv.rs b/src/uu/pwconv/src/pwconv.rs
index 3663658..5ecb150 100644
--- a/src/uu/pwconv/src/pwconv.rs
+++ b/src/uu/pwconv/src/pwconv.rs
@@ -598,7 +598,7 @@ mod tests {
         reconcile_gshadow(&mut gr, &mut gs);
         assert_eq!(gr[0].passwd, "x");
         assert_eq!(gs[0].passwd, "$6$t$t");
-        assert!(gs[0].admins.is_empty());
+        assert!(gs[0].admins.is_empty(), "{:?}", gs[0].admins);
         assert_eq!(gs[0].members, vec!["alice".to_string(), "bob".to_string()]);
     }
 
diff --git a/tests/by-util/test_expiry.rs b/tests/by-util/test_expiry.rs
index 9b6b894..33a8772 100644
--- a/tests/by-util/test_expiry.rs
+++ b/tests/by-util/test_expiry.rs
@@ -105,7 +105,7 @@ fn test_locked_is_silent() {
     let dir = prefix("root:!$6$x$y:0:0:1:7:::");
     let out = expiry(&dir, &["-c"]);
     out.assert_code(0);
-    assert!(out.stdout.is_empty());
+    assert!(out.stdout.is_empty(), "{:?}", out.stdout);
 }
 
 /// No shadow line for the caller: no policy to enforce.