Add transaction modal flow (#633)

* Add transaction modal flow

* Preserve decimals when creating transactions

test/controllers/transactions_controller_test.rb

@@ -16,6 +16,12 @@ class TransactionsControllerTest < ActionDispatch::IntegrationTest
     assert_response :success
   end
 
+  test "prefills account_id if provided" do
+    get new_transaction_url(account_id: @transaction.account_id)
+    assert_response :success
+    assert_select "option[selected][value='#{@transaction.account_id}']"
+  end
+
   test "should create transaction" do
     name = "transaction_name"
     assert_difference("Transaction.count") do
@@ -25,6 +31,51 @@ class TransactionsControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to transactions_url
   end
 
+  test "creation preserves decimals" do
+    assert_difference("Transaction.count") do
+      post transactions_url, params: { transaction: {
+        nature: "expense",
+        account_id: @transaction.account_id,
+        amount: 123.45,
+        currency: @transaction.currency,
+        date: @transaction.date,
+        name: @transaction.name } }
+    end
+
+    assert_redirected_to transactions_url
+    assert_equal 123.45.to_d, Transaction.order(created_at: :desc).first.amount
+  end
+
+  test "expenses are positive" do
+    assert_difference("Transaction.count") do
+      post transactions_url, params: { transaction: {
+        nature: "expense",
+        account_id: @transaction.account_id,
+        amount: @transaction.amount,
+        currency: @transaction.currency,
+        date: @transaction.date,
+        name: @transaction.name } }
+    end
+
+    assert_redirected_to transactions_url
+    assert Transaction.order(created_at: :desc).first.amount.positive?, "Amount should be positive"
+  end
+
+  test "incomes are negative" do
+    assert_difference("Transaction.count") do
+      post transactions_url, params: { transaction: {
+        nature: "income",
+        account_id: @transaction.account_id,
+        amount: @transaction.amount,
+        currency: @transaction.currency,
+        date: @transaction.date,
+        name: @transaction.name } }
+    end
+
+    assert_redirected_to transactions_url
+    assert Transaction.order(created_at: :desc).first.amount.negative?, "Amount should be negative"
+  end
+
   test "should show transaction" do
     get transaction_url(@transaction)
     assert_response :success