Make \copy case-insensitive (#152)

`\COPY` behaves exactly like `\copy` in `psql` - see [psql's
slash-command-parsing
function](https://github.com/postgres/postgres/blob/ea15816928c1bbcab749205a263d82daea28a3e0/src/bin/psql/command.c#L330)
and note the use of `pg_strcasecmp`. So some users expect to be able to
use `\COPY` in pgcli. This commit makes that happen.

Author: jdpopkin

Diff for: changelog.rst

@@ -1,3 +1,8 @@
+Upcoming
+========
+
+* Made `\copy` case-insensitive, as it is in `psql`.
+
 2.1.2 (2024-05-15)
 ==================
 

Diff for: pgspecial/iocommands.py

@@ -132,6 +132,7 @@ def _index_of_file_name(tokenlist):
     "\\copy",
     "\\copy [tablename] to/from [filename]",
     "Copy data between a file and a table.",
+    case_sensitive=False,
 )
 def copy(cur, pattern, verbose):
     """Copies table data to/from files"""

Diff for: tests/test_specials.py

@@ -1034,6 +1034,18 @@ def test_slash_copy_from_csv(executor, connection, tmpdir):
     assert row[1] == "elephant"
 
 
+@dbtest
+def test_slash_copy_case_insensitive(executor, tmpdir):
+    filepath = tmpdir.join("pycons.tsv")
+    executor(
+        r"\COPY (SELECT 'Montréal', 'Portland', 'Cleveland') TO '{0}' ".format(filepath)
+    )
+    infile = filepath.open(encoding="utf-8")
+    contents = infile.read()
+    assert len(contents.splitlines()) == 1
+    assert "Montréal" in contents
+
+
 @dbtest
 def test_slash_sf(executor):
     results = executor(r"\sf func1")