Update minibox filter function to support multiple tag separators (#112)

* changed MiniBox filter function to accomidate more than 1 TAG_SEPARATOR. Updated unit test

* updated docstring

* formatting fix

* another docstring amendment

* changed MiniBox split to only split on first TAG_Separator. Added test that searches for subcode instead of code and returns empty.

* adding test that tries to use filter to access parameter with no tag separator and returns empty

* Update src/arcade/core/util/MiniBox.java

Co-authored-by: Jessica S. Yu <[email protected]>

* edited tests for clarity

* changed test to make code not first and filter on code, instead of making code first and filtering on subcode

---------

Co-authored-by: Jessica S. Yu <[email protected]>

src/arcade/core/util/MiniBox.java

@@ -158,19 +158,19 @@ public void put(String id, String val) {
     }
 
     /**
-     * Filters keys by the given code.
+     * Filters entries for keys starting with given code.
      *
-     * <p>Entries in the form "key = value" where key = code/subkey can be filtered. The returned
-     * box contains all entries in the form "subkey = value" for all entries where the code matches
-     * the given code.
+     * <p>Returns a MiniBox containing entries where the keys start with "code/" followed by any
+     * number of subkeys. The keys in the returned MiniBox exclude the initial "code/" prefix and
+     * consist only of the subkeys. The values are the same as the original MiniBox.
      *
      * @param code the code to filter by
      * @return the filtered box
      */
     public MiniBox filter(String code) {
         MiniBox results = new MiniBox();
         for (String key : keys) {
-            String[] split = key.split(TAG_SEPARATOR);
+            String[] split = key.split(TAG_SEPARATOR, 2);
             if (split.length == 2 && split[0].equals(code)) {
                 results.put(split[1], contents.get(key));
             }

test/arcade/core/util/MiniBoxTest.java

@@ -333,28 +333,60 @@ public void filter_multipleCodes_returnsFiltered() {
         MiniBox box = new MiniBox();
         String code1 = randomString();
         String code2 = randomString();
+        String subcode = randomString();
         String key1 = randomString();
         String key2 = randomString();
         String key3 = randomString();
+        String key4 = randomString();
         String value1 = randomString();
         String value2 = randomString();
         String value3 = randomString();
+        String value4 = randomString();
 
         box.put(key1, value1);
         box.put(code1 + TAG_SEPARATOR + key2, value2);
         box.put(code2 + TAG_SEPARATOR + key3, value3);
+        box.put(code2 + TAG_SEPARATOR + subcode + TAG_SEPARATOR + key4, value4);
 
         ArrayList<String> filteredKeys = new ArrayList<>();
         filteredKeys.add(key3);
+        filteredKeys.add(subcode + TAG_SEPARATOR + key4);
 
         HashMap<String, String> filteredMap = new HashMap<>();
         filteredMap.put(key3, value3);
+        filteredMap.put(subcode + TAG_SEPARATOR + key4, value4);
 
         MiniBox filtered = box.filter(code2);
         assertEquals(filteredKeys, filtered.keys);
         assertEquals(filteredMap, filtered.contents);
     }
 
+    @Test
+    void filter_codeNotFirst_returnsEmpty() {
+        MiniBox box = new MiniBox();
+        String code = randomString();
+        String subcode = randomString();
+        String value = randomString();
+
+        box.put(subcode + TAG_SEPARATOR + code, value);
+
+        MiniBox filtered = box.filter(code);
+        assertTrue(filtered.keys.isEmpty());
+        assertTrue(filtered.contents.isEmpty());
+    }
+
+    @Test
+    void filter_noTagSeparator_returnsEmpty() {
+        MiniBox box = new MiniBox();
+        String key = randomString();
+        String value = randomString();
+        box.put(key, value);
+
+        MiniBox filtered = box.filter(key);
+        assertTrue(filtered.keys.isEmpty());
+        assertTrue(filtered.contents.isEmpty());
+    }
+
     @Test
     public void compare_sameContents_returnsTrue() {
         MiniBox boxA = new MiniBox();