stages: add tests to org.osbuild.ovf

Add some tests for org.osbuild.ovf.

Extracted from https://github.com/osbuild/osbuild/pull/1751

stages/test/test_ovf.py

@@ -0,0 +1,52 @@
+#!/usr/bin/python3
+
+import pytest
+
+from osbuild import testutil
+
+STAGE_NAME = "org.osbuild.ovf"
+
+
+# Prepare dataset containing good and bad API call parameters
+@pytest.mark.parametrize("test_data, expected_err", [
+    # Bad API parameters
+    ({}, "'vmdk' is a required property"),
+    ({"vmdk": 123}, "123 is not of type 'string'"),
+    ({"vmdk": "imagename"}, "'imagename' does not match '[a-zA-Z0-9+_.-]+.vmdk'"),
+    # Good API parameters
+    ({"vmdk": "imagename.vmdk"}, ""),
+])
+# This test validates only API calls using correct and incorrect queries
+def test_schema_validation_ovf(stage_schema, test_data, expected_err):
+    test_input = {
+        "type": STAGE_NAME,
+        "devices": {
+            "device": {
+                "path": "some-path",
+            },
+        },
+        "options": {
+        }
+    }
+    test_input["options"].update(test_data)
+    res = stage_schema.validate(test_input)
+
+    if expected_err == "":
+        assert res.valid is True, f"err: {[e.as_dict() for e in res.errors]}"
+    else:
+        assert res.valid is False
+        testutil.assert_jsonschema_error_contains(res, expected_err, expected_num_errs=1)
+
+
+@pytest.mark.skipif(not testutil.has_executable("qemu-img"), reason="need qemu-img")
+def test_ovf_default_template(tmp_path, stage_module):
+    faked_vmdk_path = tmp_path / "some-image.vmdk"
+    faked_vmdk_path.write_bytes(b"1234")
+
+    opts = {
+        "vmdk": faked_vmdk_path,
+    }
+    stage_module.main(opts, tmp_path)
+
+    expected_template_path = tmp_path / "some-image.ovf"
+    assert "other26xLinux64Guest" in expected_template_path.read_text()