Ruby: add compression integration test

ruby/ql/integration-tests/compression/methods.expected

@@ -0,0 +1 @@
+| source.rb:1:1:3:3 | f |

ruby/ql/integration-tests/compression/methods.ql

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+import codeql.ruby.AST
+
+from Method m
+select m

ruby/ql/integration-tests/compression/source.rb

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+def f
+  puts "hello"
+end

ruby/ql/integration-tests/compression/test.py

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+import pytest
+
+
+@pytest.mark.parametrize(("compression", "suffix"), [
+    pytest.param("none", [], id="none"),
+    pytest.param("gzip", [".gz"], id="gzip"),
+    pytest.param("zstd", [".zst"], id="zstd"),
+])
+def test(codeql, ruby, compression, suffix, cwd):
+    codeql.database.create(
+        _env={
+            "CODEQL_EXTRACTOR_RUBY_OPTION_TRAP_COMPRESSION": compression,
+        }
+    )
+    trap_files = [*(cwd / "test-db" / "trap").rglob("*.trap*")]
+    assert trap_files, "No trap files found"
+    expected_suffixes = [".trap"] + suffix
+
+    def is_of_expected_format(file):
+        return file.name == "metadata.trap.gz" or \
+            file.suffixes[-len(expected_suffixes):] == expected_suffixes
+
+    files_with_wrong_format = [
+        f for f in trap_files if not is_of_expected_format(f)
+    ]
+    assert not files_with_wrong_format, f"Found trap files with wrong format"