Extend import test files

test/import/invalid-currency.csv

@@ -1,2 +1,2 @@
 Date,Code,Currency,Price,Quantity,Action,Fee
-12/12/2021,BTC,EUR,44558.42,1,buy,0
+12/12/2021,BTC,XYZ,44558.42,1,buy,0

test/import/unavailable-exchange-rate.json

@@ -0,0 +1,19 @@
+{
+  "meta": {
+    "date": "2023-02-05T00:00:00.000Z",
+    "version": "dev"
+  },
+  "activities": [
+    {
+      "comment": null,
+      "fee": 0,
+      "quantity": 0,
+      "type": "BUY",
+      "unitPrice": 0,
+      "currency": "EUR",
+      "dataSource": "YAHOO",
+      "date": "1990-01-01T22:00:00.000Z",
+      "symbol": "MSFT"
+    }
+  ]
+}