oppia-android: Fraction type JSONObject Parsing Error

Describe the bug Fraction’s rule type HasIntegerPartEqualTo is not parsing correctly.

To Reproduce Steps to reproduce the behavior:

1. Go to Chapter 6 - Mixed Numbers and the Number line (Alpha Data only)
2. Nothing will show on screen

Expected behavior The data should be parsed correctly.

Demonstration

Environment

• Device/emulator being used: emulator
• Android or SDK version (e.g. Android 5 or SDK 21): SDK 28
• App version (you can get this through system app settings or via the admin controls menu in-app): 1 with data from the assets repository

Additional context Error Log

/org.oppia.android E/StateFragment: Failed to retrieve ephemeral state
    org.json.JSONException: Value 0 at x of type java.lang.Integer cannot be converted to JSONObject
        at org.json.JSON.typeMismatch(JSON.java:101)
        at org.json.JSONObject.getJSONObject(JSONObject.java:616)
        at org.oppia.android.domain.util.StateRetriever.createExactInputForFractionInput(StateRetriever.kt:330)
        at org.oppia.android.domain.util.StateRetriever.createExactInputFromJson(StateRetriever.kt:301)
        at org.oppia.android.domain.util.StateRetriever.convertToRuleSpec(StateRetriever.kt:263)
        at org.oppia.android.domain.util.StateRetriever.createSingleAnswerGroupFromJson(StateRetriever.kt:126)
        at org.oppia.android.domain.util.StateRetriever.createAnswerGroupsFromJson(StateRetriever.kt:94)
        at org.oppia.android.domain.util.StateRetriever.createInteractionFromJson(StateRetriever.kt:67)
        at org.oppia.android.domain.util.StateRetriever.createStateFromJson(StateRetriever.kt:49)
        at org.oppia.android.domain.exploration.ExplorationRetriever.createStatesFromJsonObject(ExplorationRetriever.kt:58)
        at org.oppia.android.domain.exploration.ExplorationRetriever.loadExplorationFromAsset(ExplorationRetriever.kt:46)
        at org.oppia.android.domain.exploration.ExplorationRetriever.loadExploration(ExplorationRetriever.kt:33)
        at org.oppia.android.domain.exploration.ExplorationProgressController.retrieveCurrentStateWithinCacheAsync(ExplorationProgressController.kt:463)
        at org.oppia.android.domain.exploration.ExplorationProgressController.retrieveCurrentStateAsync(ExplorationProgressController.kt:446)
        at org.oppia.android.domain.exploration.ExplorationProgressController$getCurrentState$1.invokeSuspend(ExplorationProgressController.kt:438)
        at org.oppia.android.domain.exploration.ExplorationProgressController$getCurrentState$1.invoke(Unknown Source:10)
        at org.oppia.android.util.data.AsyncResult$transformAsync$2.invokeSuspend(AsyncResult.kt:90)
        at org.oppia.android.util.data.AsyncResult$transformAsync$2.invoke(Unknown Source:10)
        at org.oppia.android.util.data.AsyncResult.transformWithResultAsync(AsyncResult.kt:147)
        at org.oppia.android.util.data.AsyncResult.transformAsync(AsyncResult.kt:89)
        at org.oppia.android.util.data.DataProviders$Companion$transformAsync$1.retrieveData(DataProviders.kt:73)
        at org.oppia.android.util.data.DataProviders$NotifiableAsyncLiveData.retrieveFromDataProvider(DataProviders.kt:364)
        at org.oppia.android.util.data.DataProviders$NotifiableAsyncLiveData.handleDataProviderUpdate(DataProviders.kt:352)
        at org.oppia.android.util.data.DataProviders$NotifiableAsyncLiveData$onActive$job$1.invokeSuspend(DataProviders.kt:311)

Data

"rule_specs": [{
"rule_type": "HasIntegerPartEqualTo",
"inputs": {
  "x": 0
}
}, {
"rule_type": "HasIntegerPartEqualTo",
"inputs": {
  "x": 1
}
}, {
"rule_type": "HasIntegerPartEqualTo",
"inputs": {
  "x": 2
}
}],

To Fix

1. Open file oppia-android/domain/src/main/assets/test_exp_id_2.json
2. Go to line 407 - https://github.com/oppia/oppia-android/blob/88f25ec53337dadbbf5c73db537257cc8c7484a6/domain/src/main/assets/test_exp_id_2.json#L407
3. Add 1 more rule type

{
   "rule_type": "HasIntegerPartEqualTo",
        "inputs": {
            "x": 1
         }
 }

it will look like this after adding

"rule_specs": [{
              "rule_type": "IsExactlyEqualTo",
              "inputs": {
                "f": {
                  "isNegative": false,
                  "wholeNumber": 0,
                  "numerator": 1,
                  "denominator": 2
                }
              }
            },
              {
                "rule_type": "HasIntegerPartEqualTo",
                "inputs": {
                  "x": 1
                }
              }],

1. Uninstall the already installed oppia app if there is any on your testing device
2. Install app and open First Test Topic
3. Nothing will be shown on screen and error will occur on logcat.
4. Now, add the logic to parse new rule - https://github.com/oppia/oppia-android/issues/4202#issuecomment-1042790267
5. re-install the app and open First Test Topic, it will work fine now.