Keysets per seed and postgres (#400)

* allow generation of keys per seed phrase

* emit errors correctly

* parse timestamps for melt and mint quotes correctly

* error messages

* adjust error message

* postgres works

* prepare postgres tests

* timestamps refactor

* add command to key activation

* generate keys per seed

* add keyset tests

* keyest uniqueness constaint on (derivation_path, seed)

* add tables ony if not exists

* log leve

tests/test_mint_db.py

@@ -0,0 +1,63 @@
+import pytest
+import pytest_asyncio
+
+from cashu.core.base import PostMeltQuoteRequest
+from cashu.mint.ledger import Ledger
+from cashu.wallet.wallet import Wallet
+from cashu.wallet.wallet import Wallet as Wallet1
+from tests.conftest import SERVER_ENDPOINT
+
+
+async def assert_err(f, msg):
+    """Compute f() and expect an error message 'msg'."""
+    try:
+        await f
+    except Exception as exc:
+        if msg not in str(exc.args[0]):
+            raise Exception(f"Expected error: {msg}, got: {exc.args[0]}")
+        return
+    raise Exception(f"Expected error: {msg}, got no error")
+
+
+@pytest_asyncio.fixture(scope="function")
+async def wallet1(ledger: Ledger):
+    wallet1 = await Wallet1.with_db(
+        url=SERVER_ENDPOINT,
+        db="test_data/wallet1",
+        name="wallet1",
+    )
+    await wallet1.load_mint()
+    yield wallet1
+
+
+@pytest.mark.asyncio
+async def test_mint_quote(wallet1: Wallet, ledger: Ledger):
+    invoice = await wallet1.request_mint(128)
+    assert invoice is not None
+    quote = await ledger.crud.get_mint_quote(quote_id=invoice.id, db=ledger.db)
+    assert quote is not None
+    assert quote.quote == invoice.id
+    assert quote.amount == 128
+    assert quote.unit == "sat"
+    assert not quote.paid
+    assert quote.checking_id == invoice.payment_hash
+    assert quote.paid_time is None
+    assert quote.created_time
+
+
+@pytest.mark.asyncio
+async def test_melt_quote(wallet1: Wallet, ledger: Ledger):
+    invoice = await wallet1.request_mint(128)
+    assert invoice is not None
+    melt_quote = await ledger.melt_quote(
+        PostMeltQuoteRequest(request=invoice.bolt11, unit="sat")
+    )
+    quote = await ledger.crud.get_melt_quote(quote_id=melt_quote.quote, db=ledger.db)
+    assert quote is not None
+    assert quote.quote == melt_quote.quote
+    assert quote.amount == 128
+    assert quote.unit == "sat"
+    assert not quote.paid
+    assert quote.checking_id == invoice.payment_hash
+    assert quote.paid_time is None
+    assert quote.created_time