Improve test case for experimental API remove_matches in library/allo…

…c/tests/string.rs

library/alloc/tests/string.rs

@@ -368,29 +368,73 @@ fn remove_bad() {
 
 #[test]
 fn test_remove_matches() {
+    // test_single_pattern_occurrence
     let mut s = "abc".to_string();
-
     s.remove_matches('b');
     assert_eq!(s, "ac");
+    // repeat_test_single_pattern_occurrence
     s.remove_matches('b');
     assert_eq!(s, "ac");
 
+    // test_single_character_pattern
     let mut s = "abcb".to_string();
-
     s.remove_matches('b');
     assert_eq!(s, "ac");
 
+    // test_pattern_with_special_characters
     let mut s = "ศไทย中华Việt Nam; foobarศ".to_string();
     s.remove_matches('ศ');
     assert_eq!(s, "ไทย中华Việt Nam; foobar");
 
+    // test_pattern_empty_text_and_pattern
     let mut s = "".to_string();
     s.remove_matches("");
     assert_eq!(s, "");
 
+    // test_pattern_empty_text
+    let mut s = "".to_string();
+    s.remove_matches("something");
+    assert_eq!(s, "");
+
+    // test_empty_pattern
+    let mut s = "Testing with empty pattern.".to_string();
+    s.remove_matches("");
+    assert_eq!(s, "Testing with empty pattern.");
+
+    // test_multiple_consecutive_patterns_1
     let mut s = "aaaaa".to_string();
     s.remove_matches('a');
     assert_eq!(s, "");
+
+    // test_multiple_consecutive_patterns_2
+    let mut s = "Hello **world****today!**".to_string();
+    s.remove_matches("**");
+    assert_eq!(s, "Hello worldtoday!");
+
+    // test_case_insensitive_pattern
+    let mut s = "CASE ** SeNsItIvE ** PaTtErN.".to_string();
+    s.remove_matches("sEnSiTiVe");
+    assert_eq!(s, "CASE ** SeNsItIvE ** PaTtErN.");
+
+    // test_pattern_with_digits
+    let mut s = "123 ** 456 ** 789".to_string();
+    s.remove_matches("**");
+    assert_eq!(s, "123  456  789");
+
+    // test_pattern_occurs_after_empty_string
+    let mut s = "abc X defXghi".to_string();
+    s.remove_matches("X");
+    assert_eq!(s, "abc  defghi");
+
+    // test_large_pattern
+    let mut s = "aaaXbbbXcccXdddXeee".to_string();
+    s.remove_matches("X");
+    assert_eq!(s, "aaabbbcccdddeee");
+
+    // test_pattern_at_multiple_positions
+    let mut s = "Pattern ** found ** multiple ** times ** in ** text.".to_string();
+    s.remove_matches("**");
+    assert_eq!(s, "Pattern  found  multiple  times  in  text.");
 }
 
 #[test]