sqlite-utils insert --sniff option, closes #230

tests/sniff/example1.csv

@@ -0,0 +1,5 @@
+id,species,name,age
+1,dog,Cleo,5
+2,dog,Pancakes,4
+3,cat,Mozie,8
+4,spider,"Daisy, the tarantula",6

tests/sniff/example2.csv

@@ -0,0 +1,5 @@
+id;species;name;age
+1;dog;Cleo;5
+2;dog;Pancakes;4
+3;cat;Mozie;8
+4;spider;"Daisy, the tarantula";6

tests/sniff/example3.csv

@@ -0,0 +1,5 @@
+id,species,name,age
+1,dog,Cleo,5
+2,dog,Pancakes,4
+3,cat,Mozie,8
+4,spider,'Daisy, the tarantula',6

tests/sniff/example4.csv

@@ -0,0 +1,5 @@
+id	species	name	age
+1	dog	Cleo	5
+2	dog	Pancakes	4
+3	cat	Mozie	8
+4	spider	'Daisy, the tarantula'	6

tests/test_sniff.py

@@ -0,0 +1,25 @@
+from sqlite_utils import cli, Database
+from click.testing import CliRunner
+import pathlib
+import pytest
+
+sniff_dir = pathlib.Path(__file__).parent / "sniff"
+
+
+@pytest.mark.parametrize("filepath", sniff_dir.glob("example*"))
+def test_sniff(tmpdir, filepath):
+    db_path = str(tmpdir / "test.db")
+    runner = CliRunner()
+    result = runner.invoke(
+        cli.cli,
+        ["insert", db_path, "creatures", str(filepath), "--sniff"],
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0, result.stdout
+    db = Database(db_path)
+    assert list(db["creatures"].rows) == [
+        {"id": "1", "species": "dog", "name": "Cleo", "age": "5"},
+        {"id": "2", "species": "dog", "name": "Pancakes", "age": "4"},
+        {"id": "3", "species": "cat", "name": "Mozie", "age": "8"},
+        {"id": "4", "species": "spider", "name": "Daisy, the tarantula", "age": "6"},
+    ]