add sqlite coin chooser test

tests/unit/wallet/test_transaction.py

@@ -424,3 +424,68 @@ class TransactionIOBalancing(AsyncioTestCase):
         self.assertListEqual([0.01, 1], self.inputs(tx))
         # change is now needed to consume extra input
         self.assertListEqual([0.97], self.outputs(tx))
+
+    async def test_basic_use_cases_sqlite(self):
+        self.ledger.coin_selection_strategy = 'sqlite'
+        self.ledger.fee_per_byte = int(.01*CENT)
+
+        # available UTXOs for filling missing inputs
+        utxos = await self.create_utxos([
+            1, 1, 3, 5, 10
+        ])
+        # pay 3 coins (3.07 w/ fees)
+        tx = await self.tx(
+            [],            # inputs
+            [self.txo(3)]  # outputs
+        )
+        # there are 4x 1.0 utxos available
+        self.assertListEqual(self.inputs(tx), [1.0, 1.0, 1.0, 1.0])
+
+        # a change of 0.93 is added to reach balance
+        self.assertListEqual(self.outputs(tx), [3, 0.93])
+
+        await self.ledger.release_outputs(utxos)
+
+        # pay 6.917 coins (7.00 w/ fees)
+        tx = await self.tx(
+            [],               # inputs
+            [self.txo(6.917)]  # outputs
+        )
+
+        self.assertListEqual(self.inputs(tx), [1.0, 1.0, 1.0, 1.0, 3.0])
+        self.assertListEqual(self.outputs(tx), [6.92])
+
+        await self.ledger.release_outputs(utxos)
+
+        # supplied input and output, but input is not enough to cover output
+        tx = await self.tx(
+            [self.txi(self.txo(10))],  # inputs
+            [self.txo(11)]             # outputs
+        )
+        # additional input is chosen (UTXO 1)
+        self.assertListEqual([10, 1.0, 1.0], self.inputs(tx))
+        # change is now needed to consume extra input
+        self.assertListEqual([11, 0.95], self.outputs(tx))
+
+        await self.ledger.release_outputs(utxos)
+
+        # liquidating a UTXO
+        tx = await self.tx(
+            [self.txi(self.txo(10))],  # inputs
+            []                         # outputs
+        )
+        self.assertListEqual([10], self.inputs(tx))
+        # missing change added to consume the amount
+        self.assertListEqual([9.98], self.outputs(tx))
+
+        await self.ledger.release_outputs(utxos)
+
+        # liquidating at a loss, requires adding extra inputs
+        tx = await self.tx(
+            [self.txi(self.txo(0.01))],  # inputs
+            []                           # outputs
+        )
+        # UTXO 1 is added to cover some of the fee
+        self.assertListEqual([0.01, 1], self.inputs(tx))
+        # change is now needed to consume extra input
+        self.assertListEqual([0.97], self.outputs(tx))