use assert_eq instead of x == y. Better output in case of error

tests/by-util/test_install.rs

@@ -483,7 +483,7 @@ fn test_install_copy_then_compare_file() {
     file2_meta = at.metadata(file2);
     let after = FileTime::from_last_modification_time(&file2_meta);
 
-    assert!(before == after);
+    assert_eq!(before, after);
 }
 
 #[test]

tests/by-util/test_printenv.rs

@@ -26,5 +26,5 @@ fn test_get_var() {
         .succeeds();
 
     assert!(!result.stdout_str().is_empty());
-    assert!(result.stdout_str().trim() == "VALUE");
+    assert_eq!(result.stdout_str().trim(), "VALUE");
 }

tests/by-util/test_touch.rs

@@ -427,7 +427,7 @@ fn test_touch_mtime_dst_succeeds() {
 
     let target_time = str_to_filetime("%Y%m%d%H%M", "202103140300");
     let (_, mtime) = get_file_times(&at, file);
-    assert!(target_time == mtime);
+    assert_eq!(target_time, mtime);
 }
 
 // is_dst_switch_hour returns true if timespec ts is just before the switch