feat(cli): neatly handle invalid directory

Raise a user friendly CLick error
if user passes a directory that doesn't exist to the read command.

Closes #5

heave/cli.py

@@ -1,5 +1,5 @@
 """Heave CLI."""
-
+from pathlib import Path
 
 import click
 from sqlalchemy import create_engine
@@ -102,7 +102,7 @@ def cli(
 
 
 @cli.command()
-@click.argument("path", type=click.Path(exists=True))
+@click.argument("path", type=click.Path(exists=True, readable=True, path_type=Path))
 @click.option("-t", "--table", required=True, help="Table to insert into.")
 @click.option("-s", "--schema", help="Table schema name.")
 @click.option(
@@ -112,7 +112,7 @@ def cli(
     help="Handle conflict errors.",
 )
 @click.pass_obj
-def insert(obj, path: str, table: str, schema: str | None, on_conflict: str | None):
+def insert(obj, path: Path, table: str, schema: str | None, on_conflict: str | None):
     """Insert data from a file into a table."""
     data = file.read_csv(path)
     sql_table = sql.reflect_table(obj, table, schema)
@@ -121,12 +121,14 @@ def insert(obj, path: str, table: str, schema: str | None, on_conflict: str | No
 
 
 @cli.command()
-@click.argument("path", type=click.Path(exists=False))
+@click.argument("path", type=click.Path(exists=False, writable=True, path_type=Path))
 @click.option("-t", "--table", required=True, help="Table to read.")
 @click.option("-s", "--schema", help="Table schema name.")
 @click.pass_obj
-def read(obj, path: str, table: str, schema: str | None):
+def read(obj, path: Path, table: str, schema: str | None):
     """Read data from a table and write it to a file."""
+    if not (d := path.parent).exists():
+        raise click.ClickException(f"No such directory: '{d}'")
     sql_table = sql.reflect_table(obj, table, schema)
     data = sql.read(obj, sql_table)
     file.write_csv(data, path)

heave/file.py

@@ -1,5 +1,6 @@
 """Extract tabular data into a custom Table object."""
 import csv
+from pathlib import Path
 
 
 class Table:
@@ -24,15 +25,15 @@ def __eq__(self, other):
         return self._data == other._data
 
 
-def read_csv(file: str) -> Table:
+def read_csv(file: Path) -> Table:
     """Read a csv file and return a Table."""
     with open(file, newline="") as f:
         reader = csv.reader(f)
         data = [tuple(row) for row in reader]
     return Table(data)
 
 
-def write_csv(data: Table, file: str) -> None:
+def write_csv(data: Table, file: Path) -> None:
     """Write a Table to a csv file."""
     with open(file, "w", newline="") as f:
         writer = csv.writer(f)

tests/test_cli.py

@@ -1,6 +1,7 @@
 """Test CLI."""
 
 import os
+from pathlib import Path
 from unittest.mock import ANY, Mock
 
 import pytest
@@ -117,9 +118,9 @@ def test_insert_schema(self, runner, monkeypatch):
         mock_reflect_table = Mock()
         monkeypatch.setattr("heave.sql.reflect_table", mock_reflect_table)
         runner.invoke(
-            cli, ["insert", "--schema", "time", "--table", "clock", self.test_file]
+            cli, ["insert", "--schema", "sales", "--table", "record", self.test_file]
         )
-        mock_reflect_table.assert_called_with(ANY, "clock", "time")
+        mock_reflect_table.assert_called_with(ANY, "record", "sales")
 
     def test_insert_error(self, runner, monkeypatch):
         """Test that changes are rolled back on error."""
@@ -136,7 +137,7 @@ def test_insert_error(self, runner, monkeypatch):
         assert result.exit_code == 1
         result = runner.invoke(cli, ["read", "--table", "user", self.test_file])
         assert result.exit_code == 0
-        table = file.read_csv(self.test_file)
+        table = file.read_csv(Path(self.test_file))
         for row in table.rows:
             assert row[1] != "jane.doe"
 
@@ -158,7 +159,10 @@ def test_insert_conflict_invalid(self, runner):
             cli, ["insert", "--table", "user", "--on-conflict", "foo", self.test_file]
         )
         assert result.exit_code == 2
-        assert "Error: Invalid value for '--on-conflict': 'foo' is not one of 'nothing', 'update'."
+        assert (
+            "Error: Invalid value for '-oc' / '--on-conflict': 'foo' is not one of 'nothing', 'update'."
+            in result.output
+        )
 
     def test_read(self, runner, monkeypatch):
         """Test the read command."""
@@ -174,6 +178,12 @@ def test_read_schema(self, runner, monkeypatch):
         mock_reflect_table = Mock()
         monkeypatch.setattr("heave.sql.reflect_table", mock_reflect_table)
         runner.invoke(
-            cli, ["read", "--schema", "time", "--table", "clock", self.test_file]
+            cli, ["read", "--schema", "sales", "--table", "record", self.test_file]
         )
-        mock_reflect_table.assert_called_with(ANY, "clock", "time")
+        mock_reflect_table.assert_called_with(ANY, "record", "sales")
+
+    def test_read_invalid_directory(self, runner):
+        """Test that Click error is raised for a non-existant directory."""
+        result = runner.invoke(cli, ["read", "--table", "user", "invalid/myfile.csv"])
+        assert result.exit_code == 1
+        assert "Error: No such directory: 'invalid'" in result.output

tests/test_file.py

@@ -1,5 +1,6 @@
 """Tests for the extract module."""
 import os
+from pathlib import Path
 
 import pytest
 
@@ -21,7 +22,7 @@ def test_init(self):
 class TestCsv:
     """Test the read_csv function."""
 
-    test_file = "temp.csv"
+    test_file = Path("temp.csv")
 
     @pytest.fixture(autouse=True)
     def temp_file(self):