diff --git a/src/build.rs b/src/build.rs
index 62778b1..121d067 100644
--- a/src/build.rs
+++ b/src/build.rs
@@ -1,5 +1,6 @@
+use crate::date_time::DEFINE_SOURCE_DATE_EPOCH;
 use crate::hook::HookExt;
-use crate::{default_deny, SdResult, Shadow};
+use crate::{default_deny, SdResult, Shadow, DEFINE_SHADOW_RS};
 use is_debug::is_debug;
 use std::collections::BTreeSet;
 use std::fmt::{Display, Formatter};
@@ -128,8 +129,8 @@ impl BuildPattern {
         }
 
         other_keys.for_each(|key| println!("cargo:rerun-if-env-changed={key}"));
-        println!("cargo:rerun-if-env-changed=SOURCE_DATE_EPOCH");
-        println!("cargo:rerun-if-changed={}/shadow.rs", out_dir);
+        println!("cargo:rerun-if-env-changed={}", DEFINE_SOURCE_DATE_EPOCH);
+        println!("cargo:rerun-if-changed={}/{}", out_dir, DEFINE_SHADOW_RS);
     }
 }
 
diff --git a/src/date_time.rs b/src/date_time.rs
index 4de68f8..6206fff 100644
--- a/src/date_time.rs
+++ b/src/date_time.rs
@@ -10,19 +10,28 @@ pub enum DateTime {
     Utc(OffsetDateTime),
 }
 
+pub(crate) const DEFINE_SOURCE_DATE_EPOCH: &str = "SOURCE_DATE_EPOCH";
+
 pub fn now_date_time() -> DateTime {
     // Enable reproducibility for uses of `now_date_time` by respecting the
     // `SOURCE_DATE_EPOCH` env variable.
     //
     // https://reproducible-builds.org/docs/source-date-epoch/
-    match std::env::var_os("SOURCE_DATE_EPOCH") {
+    match std::env::var_os(DEFINE_SOURCE_DATE_EPOCH) {
         None => DateTime::now(),
         Some(timestamp) => {
             let epoch = timestamp
                 .into_string()
-                .expect("Input SOURCE_DATE_EPOCH could not be parsed")
+                .unwrap_or_else(|_| {
+                    panic!("Input {} could not be parsed", DEFINE_SOURCE_DATE_EPOCH)
+                })
                 .parse::<i64>()
-                .expect("Input SOURCE_DATE_EPOCH could not be cast to a number");
+                .unwrap_or_else(|_| {
+                    panic!(
+                        "Input {} could not be cast to a number",
+                        DEFINE_SOURCE_DATE_EPOCH
+                    )
+                });
             DateTime::Utc(OffsetDateTime::from_unix_timestamp(epoch).unwrap())
         }
     }
@@ -177,7 +186,7 @@ mod tests {
 
     #[test]
     fn test_source_date_epoch() {
-        std::env::set_var("SOURCE_DATE_EPOCH", "1628080443");
+        std::env::set_var(DEFINE_SOURCE_DATE_EPOCH, "1628080443");
         let time = now_date_time();
         assert_eq!(time.human_format(), "2021-08-04 12:34:03 +00:00");
     }
diff --git a/src/lib.rs b/src/lib.rs
index f0f0c1c..93a123e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -189,7 +189,7 @@ pub trait Format {
     fn human_format(&self) -> String;
 }
 
-const SHADOW_RS: &str = "shadow.rs";
+const DEFINE_SHADOW_RS: &str = "shadow.rs";
 
 pub const CARGO_CLIPPY_ALLOW_ALL: &str =
     "#[allow(clippy::all, clippy::pedantic, clippy::restriction, clippy::nursery)]";
@@ -469,9 +469,9 @@ impl Shadow {
         let out = {
             let path = Path::new(out_path);
             if !out_path.ends_with('/') {
-                path.join(format!("{out_path}/{SHADOW_RS}"))
+                path.join(format!("{out_path}/{DEFINE_SHADOW_RS}"))
             } else {
-                path.join(SHADOW_RS)
+                path.join(DEFINE_SHADOW_RS)
             }
         };
 
@@ -690,7 +690,7 @@ mod tests {
             .src_path("./")
             .out_path("./")
             .build()?;
-        let shadow = fs::read_to_string("./shadow.rs")?;
+        let shadow = fs::read_to_string(DEFINE_SHADOW_RS)?;
         assert!(!shadow.is_empty());
         assert!(shadow.lines().count() > 0);
         Ok(())
@@ -704,7 +704,7 @@ mod tests {
             .deny_const(BTreeSet::from([CARGO_TREE]))
             .build()?;
 
-        let shadow = fs::read_to_string("./shadow.rs")?;
+        let shadow = fs::read_to_string(DEFINE_SHADOW_RS)?;
         assert!(!shadow.is_empty());
         assert!(shadow.lines().count() > 0);
         // println!("{shadow}");