test_link.py: Add more tests and cleanup

tests/test_link.py

@@ -1,24 +1,192 @@
-from datetime import datetime
+import datetime
 import unittest
 
 import pystac
-from tests.utils import (RANDOM_BBOX, RANDOM_GEOM)
 
-TEST_DATETIME = datetime(2020, 3, 14, 16, 32)
+TEST_DATETIME: datetime.datetime = datetime.datetime(2020, 3, 14, 16, 32)
 
 
 class LinkTest(unittest.TestCase):
+    item: pystac.Item
+
+    def setUp(self):
+        self.item = pystac.Item(id='test-item',
+                                geometry=None,
+                                bbox=None,
+                                datetime=TEST_DATETIME,
+                                properties={})
+
+    def test_minimal(self):
+        rel = 'my rel'
+        target = 'https://example.com/a/b'
+        link = pystac.Link(rel, target)
+        self.assertEqual(target, link.get_href())
+        self.assertEqual(target, link.get_absolute_href())
+
+        expected_repr = f'<Link rel={rel} target={target}>'
+        self.assertEqual(expected_repr, link.__repr__())
+
+        self.assertFalse(link.is_resolved())
+
+        expected_dict = {'rel': rel, 'href': target}
+        self.assertEqual(expected_dict, link.to_dict())
+
+        # Run the same tests on the clone.
+        clone = link.clone()
+        self.assertNotEqual(link, clone)
+
+        self.assertEqual(target, clone.get_href())
+        self.assertEqual(target, clone.get_absolute_href())
+
+        self.assertEqual(expected_repr, clone.__repr__())
+
+        self.assertEqual(expected_dict, clone.to_dict())
+
+        # Try the modification methods.
+        self.assertIsNone(link.owner)
+        link.set_owner(1)  # A junk value.
+        self.assertEqual(1, link.owner)
+        link.set_owner(None)
+        self.assertIsNone(link.owner)
+
+        self.assertEqual(pystac.LinkType.ABSOLUTE, link.link_type)
+
+        link.make_absolute()
+        self.assertEqual(pystac.LinkType.ABSOLUTE, link.link_type)
+        self.assertEqual(target, link.get_href())
+        self.assertEqual(target, link.get_absolute_href())
+
+        link.make_relative()
+        self.assertEqual(pystac.LinkType.RELATIVE, link.link_type)
+        self.assertEqual(target, link.get_href())
+        self.assertEqual(target, link.get_absolute_href())
+
+        link.set_owner(self.item)
+        self.assertEqual(self.item, link.owner)
+
+    def test_relative(self):
+        rel = 'my rel'
+        target = '../elsewhere'
+        mime_type = 'example/stac_thing'
+        link = pystac.Link(rel,
+                           target,
+                           mime_type,
+                           'a title',
+                           properties={'a': 'b'},
+                           link_type=pystac.LinkType.RELATIVE)
+        expected_dict = {
+            'rel': rel,
+            'href': target,
+            'type': 'example/stac_thing',
+            'title': 'a title',
+            'a': 'b'
+        }
+        self.assertEqual(expected_dict, link.to_dict())
+
+        self.assertEqual(pystac.LinkType.RELATIVE, link.link_type)
+
     def test_link_does_not_fail_if_href_is_none(self):
-        """Test to ensure get_href does not fail when the href is None"""
+        """Test to ensure get_href does not fail when the href is None."""
         catalog = pystac.Catalog(id='test', description='test desc')
-        item = pystac.Item(id='test-item',
-                           geometry=RANDOM_GEOM,
-                           bbox=RANDOM_BBOX,
-                           datetime=datetime.utcnow(),
-                           properties={})
-        catalog.add_item(item)
+        catalog.add_item(self.item)
         catalog.set_self_href('/some/href')
         catalog.make_all_links_relative()
 
         link = catalog.get_single_link('item')
         self.assertIsNone(link.get_href())
+
+    def test_resolve_stac_object_no_root_and_target_is_item(self):
+        link = pystac.Link('my rel', target=self.item)
+        link.resolve_stac_object()
+
+
+class StaticLinkTest(unittest.TestCase):
+    def test_from_dict_round_trip(self):
+        test_cases = [
+            {
+                'rel': '',
+                'href': ''
+            },  # Not valid, but works.
+            {
+                'rel': 'r',
+                'href': 't'
+            },
+            {
+                'rel': 'r',
+                'href': '/t'
+            },
+            {
+                'rel': 'r',
+                'href': 't',
+                'type': 'a/b',
+                'title': 't',
+                'c': 'd',
+                1: 2
+            },
+            # Special case.
+            {
+                'rel': 'self',
+                'href': 't'
+            },
+        ]
+        for d in test_cases:
+            d2 = pystac.Link.from_dict(d).to_dict()
+            self.assertEqual(d, d2)
+
+    def test_from_dict_link_type(self):
+        test_cases = [
+            ({
+                'rel': '',
+                'href': 'https://a'
+            }, pystac.LinkType.ABSOLUTE),
+            ({
+                'rel': '',
+                'href': '/a'
+            }, pystac.LinkType.ABSOLUTE),
+            ({
+                'rel': '',
+                'href': 'a'
+            }, pystac.LinkType.RELATIVE),
+            ({
+                'rel': '',
+                'href': './a'
+            }, pystac.LinkType.RELATIVE),
+            # 'self' is a special case.
+            ({
+                'rel': 'self',
+                'href': 'does not matter'
+            }, pystac.LinkType.ABSOLUTE),
+        ]
+        for case in test_cases:
+            item = pystac.Link.from_dict(case[0])
+            self.assertEqual(case[1], item.link_type)
+
+    def test_from_dict_failures(self):
+        for d in [{}, {'href': 't'}, {'rel': 'r'}]:
+            with self.assertRaises(KeyError):
+                pystac.Link.from_dict(d)
+
+        for d in [
+            {
+                'rel': '',
+                'href': 1
+            },
+            {
+                'rel': '',
+                'href': None
+            },
+        ]:
+            with self.assertRaises(AttributeError):
+                pystac.Link.from_dict(d)
+
+    def test_collection(self):
+        c = pystac.Collection('collection id', 'desc', extent=None)
+        link = pystac.Link.collection(c)
+        expected = {'rel': 'collection', 'href': None, 'type': 'application/json'}
+        self.assertEqual(expected, link.to_dict())
+
+    def test_child(self):
+        c = pystac.Collection('collection id', 'desc', extent=None)
+        link = pystac.Link.child(c)
+        expected = {'rel': 'child', 'href': None, 'type': 'application/json'}
+        self.assertEqual(expected, link.to_dict())