fix(snapbi): add null-safety to minifyJson()

Author: salismidtrans

library/src/main/java/com/midtrans/snapbi/SnapBi.java

@@ -295,6 +295,9 @@ public static String getSymmetricSignatureHmacSh512(String accessToken, Map<Stri
     }
 
     static String minifyJson(String json) {
+        if (json == null || json.isEmpty()) {
+            return "";
+        }
         // Minify JSON by removing insignificant whitespace (outside of string values)
         // while preserving whitespace inside quoted strings and maintaining key order.
         StringBuilder sb = new StringBuilder(json.length());

library/src/test/java/com/midtrans/snapbi/SnapBiMinifyJsonTest.java

@@ -62,6 +62,16 @@ void emptyObjectAndArray() {
         assertEquals("[]", SnapBi.minifyJson("[ ]"));
     }
 
+    @Test
+    void nullInputReturnsEmptyString() {
+        assertEquals("", SnapBi.minifyJson(null));
+    }
+
+    @Test
+    void emptyInputReturnsEmptyString() {
+        assertEquals("", SnapBi.minifyJson(""));
+    }
+
     @Test
     void realisticSnapBiVaNotificationPayload() {
         String input = "{\n" +