improve add new transaction implementation

src/main/kotlin/Main.kt

@@ -1,10 +1,6 @@
 package org.qudus.squad
 
 
-import org.qudus.squad.testCases.testDeleteCategoryFunction
-import org.qudus.squad.testCases.testMonthlyTransactionsCases
-
-
 fun main() {
     /*TODO*/
 

src/main/kotlin/dataSource/FinanceTrackerDataSourceImpl.kt

@@ -7,37 +7,37 @@ import org.qudus.squad.logic.models.TransactionType
 
 class FinanceTrackerDataSourceImpl : FinanceTrackerDataSource {
 
-    private val categories: MutableList<Category> = emptyList<Category>().toMutableList()
+    private val _categories: MutableList<Category> =
+        mutableListOf<Category>(Category(name = "Rent") , Category(name = "Salary") , Category(name = "Food"))
     private val transactions: MutableList<Transaction> = emptyList<Transaction>().toMutableList()
+    val categories get() = this._categories
 
-    val _categories
-        get() = categories
     override fun addCategory(category: Category): Boolean {
         if (category.name.isNotEmpty()) {
-            categories.add(category)
+            this._categories.add(category)
             return true
         }
         return false
     }
 
     override fun removeCategory(categoryId: Int): Boolean {
-        return categories.removeIf {
+        return this._categories.removeIf {
             it.id == categoryId
         }
     }
 
     override fun getCategories(): List<Category> {
-        return categories
+        return this._categories
     }
 
     override fun getCategoryById(categoryId: Int): Category? {
-        return categories.find { it.id == categoryId }
+        return this._categories.find { it.id == categoryId }
     }
 
     override fun updateCategory(category: Category): Boolean {
-        val index = categories.indexOfFirst { it.id == category.id }
+        val index = this._categories.indexOfFirst { it.id == category.id }
         return if (index != -1) {
-            categories[index] = category
+            this._categories[index] = category
             true
         } else {
             false

src/main/kotlin/logic/models/Category.kt

@@ -2,14 +2,10 @@ package org.qudus.squad.logic.models
 
 data class Category(
     val id: Int = CategoryIdGenerator.nextId(),
-    var name: String
-
+    val name: String
 )
 
-
 object CategoryIdGenerator {
     private var counter = 0
     fun nextId(): Int = ++counter
-}
-
-
+}

src/main/kotlin/logic/models/Transaction.kt

@@ -1,11 +1,11 @@
 package org.qudus.squad.logic.models
 
 data class Transaction(
-    val id: Int? = TransactionIdGenerator.nextId(),
-    var type: TransactionType,
-    var amount: Double,
-    var timeStamp: Long,
-    var category: Category
+    val id: Int = TransactionIdGenerator.nextId(), //not nullable
+    val type: TransactionType,
+    val amount: Double,
+    val timeStamp: Long,
+    val category: Category
 )
 
 object TransactionIdGenerator {
@@ -14,7 +14,5 @@ object TransactionIdGenerator {
 }
 
 enum class TransactionType {
-    Deposit , Withdraw
-}
-
-
+    Deposit, Withdraw
+}

src/main/kotlin/logic/transactions/AddNewTransaction.kt

@@ -7,17 +7,12 @@ import org.qudus.squad.logic.models.Transaction
 class AddNewTransaction(
     private val dataSource: FinanceTrackerDataSource
 ) {
-
-
-
-
-    fun CompleteTransaction(transaction: Transaction) {
+    fun addNewTransaction(transaction: Transaction) {
         if (isAmountValid(transaction)) {
             dataSource.addTransaction(transaction)
         }
     }
 
     fun isAmountValid(transaction: Transaction): Boolean = transaction.amount < 0
-
 }
 

src/main/kotlin/testCases/TestCasesA.kt

@@ -1,6 +1,4 @@
-/*
-package org.qudus.squad.testCases
-
+package org.qudus.squad.testCases/*
 fun main() {
 
    */