[#1878] Update SystemTestUtil::assertJson to compare Json objects i…

…nstead of line-by-line analysis (#2087)

`SystemTestUtil::assertJson` currently checks if two JSON files are
equal by comparing the file contents line by line rather than by
converting the files directly into JSON objects, which can then be
directly compared using the built-in `equals` methods for
`JsonElement`.

This process also does not automatically check if the file is indeed a
JSON file, and implicitly assumes that the input paths are paths to
JSON files. This may cause expected behaviours if a user accidentally
or intentionally includes a path to a non-JSON file within the method
calls.

Let's move to refactor the code, and utilise the built-in methods for
`JsonElement` objects to check for the equality of JSON objects.

src/systemtest/java/reposense/util/SystemTestUtil.java

@@ -9,6 +9,7 @@
 
 import org.junit.jupiter.api.Assertions;
 
+import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 
@@ -63,10 +64,16 @@ public static void assertSummaryJson(Path expectedSummaryJsonPath, Path actualSu
      */
     public static void assertJson(Path expectedJsonPath, Path actualJsonPath) {
         Assertions.assertTrue(Files.exists(actualJsonPath));
-        try {
-            Assertions.assertTrue(TestUtil.compareFileContents(expectedJsonPath, actualJsonPath));
-        } catch (Exception e) {
-            Assertions.fail(e.getMessage());
+
+        try (FileReader fileReaderExpected = new FileReader(expectedJsonPath.toFile());
+                FileReader fileReaderActual = new FileReader(actualJsonPath.toFile())) {
+
+            JsonElement jsonExpected = JsonParser.parseReader(fileReaderExpected);
+            JsonElement jsonActual = JsonParser.parseReader(fileReaderActual);
+
+            Assertions.assertEquals(jsonExpected, jsonActual);
+        } catch (IOException ex) {
+            Assertions.fail(ex.getMessage());
         }
     }
 }