Merge branch 'mb/diogenes' into develop

8 files changed, 189 insertions, 81 deletions

diff --git a/test/extractor/generic/test_constant.py b/test/extractor/generic/test_constant.py
index bde3805..77ee02b 100644
--- a/test/extractor/generic/test_constant.py
+++ b/test/extractor/generic/test_constant.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import unittest
 
@@ -20,11 +15,11 @@ class TestConstant(unittest.TestCase):
     def test_extract(self):
         schema = '''
             bse:author rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "true"^^xsd:boolean .
             bse:comment rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "false"^^xsd:boolean .
             '''
@@ -33,10 +28,10 @@ class TestConstant(unittest.TestCase):
             (ns.bse.comment, 'the quick brown fox jumps over the lazy dog.'),
             ]
         ext = Constant(schema, tuples)
-        node = _node.Node(ns.bsfs.Entity, '') # Blank node
+        node = _node.Node(ns.bsn.Entity, '') # Blank node
         p_author = ext.schema.predicate(ns.bse.author)
         p_comment = ext.schema.predicate(ns.bse.comment)
-        entity = ext.schema.node(ns.bsfs.Node).child(ns.bsfs.Entity)
+        entity = ext.schema.node(ns.bsfs.Node).child(ns.bsn.Entity)
         string = ext.schema.literal(ns.bsfs.Literal).child(ns.xsd.string)
         # baseline
         self.assertSetEqual(set(ext.extract(node, None, (p_author, p_comment))),
@@ -55,11 +50,11 @@ class TestConstant(unittest.TestCase):
         # schema compliance
         schema = '''
             bse:author rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "true"^^xsd:boolean .
             bse:comment rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "false"^^xsd:boolean .
             '''
@@ -80,13 +75,13 @@ class TestConstant(unittest.TestCase):
     def test_eq(self):
         schema_a = '''
             bse:author rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "true"^^xsd:boolean .
             '''
         schema_b = '''
             bse:comment rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "false"^^xsd:boolean .
             '''
diff --git a/test/extractor/generic/test_path.py b/test/extractor/generic/test_path.py
index ae68686..0beb37e 100644
--- a/test/extractor/generic/test_path.py
+++ b/test/extractor/generic/test_path.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import unittest
 
@@ -31,17 +26,17 @@ class TestPath(unittest.TestCase):
         self.assertEqual(Path().schema,
             bsfs.schema.from_string(base.SCHEMA_PREAMBLE + '''
                 bse:filename rdfs:subClassOf bsfs:Predicate ;
-                    rdfs:domain bsfs:File ;
+                    rdfs:domain bsn:Entity ;
                     rdfs:range xsd:string ;
-                    bsfs:unique "false"^^xsd:boolean .
+                    bsfs:unique "true"^^xsd:boolean .
                 '''))
 
     def test_extract(self):
         ext = Path()
-        node = _node.Node(ns.bsfs.File, '') # Blank node
+        node = _node.Node(ns.bsn.Entity, '') # Blank node
         content = '/tmp/foo/bar'
         p_filename = ext.schema.predicate(ns.bse.filename)
-        entity = ext.schema.node(ns.bsfs.Node).child(ns.bsfs.Entity)
+        entity = ext.schema.node(ns.bsfs.Node).child(ns.bsn.Entity)
         string = ext.schema.literal(ns.bsfs.Literal).child(ns.xsd.string)
 
         # baseline
diff --git a/test/extractor/generic/test_stat.py b/test/extractor/generic/test_stat.py
index e5562d1..0e83e24 100644
--- a/test/extractor/generic/test_stat.py
+++ b/test/extractor/generic/test_stat.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import os
 import unittest
@@ -32,17 +27,17 @@ class TestStat(unittest.TestCase):
         self.assertEqual(Stat().schema,
             bsfs.schema.from_string(base.SCHEMA_PREAMBLE + '''
                 bse:filesize rdfs:subClassOf bsfs:Predicate ;
-                    rdfs:domain bsfs:File ;
+                    rdfs:domain bsn:Entity ;
                     rdfs:range xsd:integer ;
-                    bsfs:unique "false"^^xsd:boolean .
+                    bsfs:unique "true"^^xsd:boolean .
                 '''))
 
     def test_extract(self):
         ext = Stat()
-        node = _node.Node(ns.bsfs.File, '') # Blank node
+        node = _node.Node(ns.bsn.Entity, '') # Blank node
         content = os.stat(__file__)
         p_filesize = ext.schema.predicate(ns.bse.filesize)
-        entity = ext.schema.node(ns.bsfs.Node).child(ns.bsfs.Entity)
+        entity = ext.schema.node(ns.bsfs.Node).child(ns.bsn.Entity)
         string = ext.schema.literal(ns.bsfs.Literal).child(ns.xsd.string)
 
         # baseline
diff --git a/test/extractor/image/test_colors_spatial.py b/test/extractor/image/test_colors_spatial.py
index ba551f3..902ab6d 100644
--- a/test/extractor/image/test_colors_spatial.py
+++ b/test/extractor/image/test_colors_spatial.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import os
 import unittest
@@ -24,8 +19,8 @@ from bsie.extractor.image.colors_spatial import ColorsSpatial
 class TestColorsSpatial(unittest.TestCase):
     def setUp(self):
         # content id with default constructors (width=32, height=32, exp=4)
-        self.instance_prefix = 'http://ie.bsfs.ai/schema/Feature/ColorsSpatial'
-        self.predicate_prefix = 'http://bsfs.ai/schema/Entity/colors_spatial'
+        self.instance_prefix = 'https://schema.bsfs.io/ie/Literal/Array/Feature/ColorsSpatial'
+        self.predicate_prefix = 'https://schema.bsfs.io/ie/Node/Entity#colors_spatial_'
         self.uuid = 'adee8d6c43687021e1c5bffe56bcfe727f1638d792744137181304ef889dac2a'
 
     def test_essentials(self):
@@ -55,7 +50,7 @@ class TestColorsSpatial(unittest.TestCase):
 
     def test_schema(self):
         schema = bsfs.schema.from_string(base.SCHEMA_PREAMBLE + f'''
-            <{self.instance_prefix}> rdfs:subClassOf bsfs:Feature ;
+            <{self.instance_prefix}> rdfs:subClassOf bsa:Feature ;
                 # annotations
                 rdfs:label "Spatially dominant colors"^^xsd:string ;
                 schema:description "Domiant colors of subregions in an image."^^xsd:string ;
@@ -68,8 +63,8 @@ class TestColorsSpatial(unittest.TestCase):
                 <{self.instance_prefix}/args#height> "32"^^xsd:integer ;
                 <{self.instance_prefix}/args#exp> "4"^^xsd:float .
 
-            <{self.predicate_prefix}#{self.uuid}> rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:File ;
+            <{self.predicate_prefix}{self.uuid}> rdfs:subClassOf bsfs:Predicate ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range <{self.instance_prefix}#{self.uuid}> ;
                 bsfs:unique "true"^^xsd:boolean .
             ''')
@@ -78,7 +73,7 @@ class TestColorsSpatial(unittest.TestCase):
     def test_extract(self):
         ext = ColorsSpatial(2,2,2)
         img = PIL.Image.open(os.path.join(os.path.dirname(__file__), 'testimage.jpg'))
-        node = _node.Node(ns.bsfs.Entity, bsfs.URI('http://example.com/entity#1234'))
+        node = _node.Node(ns.bsn.Entity, bsfs.URI('http://example.com/entity#1234'))
         principals = set(ext.principals)
         self.assertEqual(len(principals), 1)
         # valid invocation yields feature
diff --git a/test/extractor/image/test_photometrics.py b/test/extractor/image/test_photometrics.py
new file mode 100644
index 0000000..fb219e2
--- /dev/null
+++ b/test/extractor/image/test_photometrics.py
@@ -0,0 +1,143 @@
+
+# standard imports
+import unittest
+
+# bsie imports
+from bsie.extractor import base
+from bsie.utils import bsfs, node as _node, ns
+
+# objects to test
+from bsie.extractor.image.photometrics import Exif, _gps_to_dec
+
+
+## code ##
+
+class TestExif(unittest.TestCase):
+
+    def test_gps_to_dec(self):
+        # deg+min+sec format
+        self.assertAlmostEqual(_gps_to_dec('29/1 58/1 45/1'.split()), 29.979167, 6)
+        self.assertAlmostEqual(_gps_to_dec('31 08 03'.split()), 31.134167, 6)
+        self.assertAlmostEqual(_gps_to_dec('20 40 586/10'.split()), 20.682944, 6)
+        self.assertAlmostEqual(_gps_to_dec('88/1 34 68/10'.split()), 88.568556, 6)
+        # deg+min format
+        self.assertAlmostEqual(_gps_to_dec('13 472167/10000 0/1 '.split()), 13.786945, 6)
+        self.assertAlmostEqual(_gps_to_dec('104/1 3215/100 0/1'.split()), 104.535833, 6)
+
+    def test_eq(self):
+        # identical instances are equal
+        self.assertEqual(Exif(), Exif())
+        self.assertEqual(hash(Exif()), hash(Exif()))
+        # comparison respects type
+        class Foo(): pass
+        self.assertNotEqual(Exif(), Foo())
+        self.assertNotEqual(hash(Exif()), hash(Foo()))
+        self.assertNotEqual(Exif(), 1234)
+        self.assertNotEqual(hash(Exif()), hash(1234))
+        self.assertNotEqual(Exif(), None)
+        self.assertNotEqual(hash(Exif()), hash(None))
+
+    def test_schema(self):
+        self.assertSetEqual({pred.uri for pred in Exif().schema.predicates()}, {
+            ns.bsfs.Predicate,
+            ns.bse.exposure,
+            ns.bse.aperture,
+            ns.bse.iso,
+            ns.bse.focal_length,
+            ns.bse.width,
+            ns.bse.height,
+            ns.bse.orientation,
+            ns.bse.orientation_label,
+            ns.bse.altitude,
+            ns.bse.latitude,
+            ns.bse.longitude,
+            })
+
+    def test_extract(self):
+        ext = Exif()
+        node = _node.Node(ns.bsfs.File, '') # Blank node
+        content = {
+            'Exif.Photo.ExposureTime': '10/600',
+            'Exif.Photo.FNumber': '48/10',
+            'Exif.Photo.ISOSpeedRatings': '400',
+            'Exif.Photo.FocalLength': '460/10',
+            'Exif.Photo.PixelXDimension': '4288',
+            'Exif.Photo.PixelYDimension': '2848',
+            'Exif.Image.Orientation': '1',
+            'Exif.GPSInfo.GPSAltitude': '431/1',
+            'Exif.GPSInfo.GPSLatitude': '46/1 11397/625 0/1',
+            'Exif.GPSInfo.GPSLongitude': '7/1 131250/2500 0/1',
+            }
+
+        # invalid principals are ignored
+        self.assertSetEqual(set(ext.extract(node, content, {ns.bse.filename})), set())
+        # extract finds all relevant information
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.exposure)})),
+            {(node, ext.schema.predicate(ns.bse.exposure), 60.0)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.aperture)})),
+            {(node, ext.schema.predicate(ns.bse.aperture), 4.8)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.iso)})),
+            {(node, ext.schema.predicate(ns.bse.iso), 400)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.focal_length)})),
+            {(node, ext.schema.predicate(ns.bse.focal_length), 46.0)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.width)})),
+            {(node, ext.schema.predicate(ns.bse.width), 4288)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.height)})),
+            {(node, ext.schema.predicate(ns.bse.height), 2848)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.orientation)})),
+            {(node, ext.schema.predicate(ns.bse.orientation), 1)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.orientation_label)})),
+            {(node, ext.schema.predicate(ns.bse.orientation_label), 'landscape')})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.altitude)})),
+            {(node, ext.schema.predicate(ns.bse.altitude), 431.0)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.latitude)})),
+            {(node, ext.schema.predicate(ns.bse.latitude), 46.30392)})
+        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.longitude)})),
+            {(node, ext.schema.predicate(ns.bse.longitude), 7.875)})
+
+        # check orientation label
+        self.assertSetEqual(set(ext.extract(
+            node, {
+                'Exif.Photo.PixelXDimension': '4288',
+                'Exif.Photo.PixelYDimension': '2848',
+                'Exif.Image.Orientation': '5',
+                },
+            {ext.schema.predicate(ns.bse.orientation_label)})),
+            {(node, ext.schema.predicate(ns.bse.orientation_label), 'portrait')})
+
+        # can pass multiple principals
+        self.assertSetEqual(set(ext.extract(node, content, {
+            ext.schema.predicate(ns.bse.exposure),
+            ext.schema.predicate(ns.bse.iso),
+            ext.schema.predicate(ns.bse.focal_length),
+            })), {
+            (node, ext.schema.predicate(ns.bse.exposure), 60.0),
+            (node, ext.schema.predicate(ns.bse.iso), 400),
+            (node, ext.schema.predicate(ns.bse.focal_length), 46.0),
+            })
+
+        # principals w/o content are ignored
+        self.assertSetEqual(set(ext.extract(
+            node,
+            content={'Exif.Photo.ExposureTime': '10/600'},
+            principals={
+                ext.schema.predicate(ns.bse.exposure),
+                ext.schema.predicate(ns.bse.iso),
+                ext.schema.predicate(ns.bse.focal_length),
+                })
+            ), {
+            (node, ext.schema.predicate(ns.bse.exposure), 60.0),
+            })
+
+        # empty content is acceptable
+        self.assertSetEqual(set(ext.extract(node, {}, set(ext.principals))), set())
+        # no principals is acceptable
+        self.assertSetEqual(set(ext.extract(node, content, set())), set())
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/extractor/test_base.py b/test/extractor/test_base.py
index acfaf58..81865e1 100644
--- a/test/extractor/test_base.py
+++ b/test/extractor/test_base.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import unittest
 
@@ -20,11 +15,11 @@ class StubExtractor(base.Extractor):
     def __init__(self):
         super().__init__(bsfs.schema.from_string(base.SCHEMA_PREAMBLE + '''
             bse:author rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "false"^^xsd:boolean .
             bse:comment rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
+                rdfs:domain bsn:Entity ;
                 rdfs:range xsd:string ;
                 bsfs:unique "false"^^xsd:boolean .
         '''))
@@ -53,8 +48,8 @@ class TestExtractor(unittest.TestCase):
 
     def test_principals(self):
         schema = bsfs.schema.Schema()
-        entity = schema.node(ns.bsfs.Node).child(ns.bsfs.Entity)
-        string = schema.literal(ns.bsfs.Literal).child(bsfs.URI('http://www.w3.org/2001/XMLSchema#string'))
+        entity = schema.node(ns.bsfs.Node).child(ns.bsn.Entity)
+        string = schema.literal(ns.bsfs.Literal).child(ns.xsd.string)
         p_author = schema.predicate(ns.bsfs.Predicate).child(ns.bse.author, domain=entity, range=string)
         p_comment = schema.predicate(ns.bsfs.Predicate).child(ns.bse.comment, domain=entity, range=string)
         ext = StubExtractor()
diff --git a/test/extractor/test_builder.py b/test/extractor/test_builder.py
index 039ea53..fbb0895 100644
--- a/test/extractor/test_builder.py
+++ b/test/extractor/test_builder.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import unittest
 
@@ -51,33 +46,33 @@ class TestExtractorBuilder(unittest.TestCase):
             {'bsie.extractor.generic.constant.Constant': {
                 'schema': '''
                     bse:author rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs:Entity ;
+                        rdfs:domain bsn:Entity ;
                         rdfs:range xsd:string ;
                         bsfs:unique "true"^^xsd:boolean .
                     bse:rating rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs:Entity ;
+                        rdfs:domain bsn:Entity ;
                         rdfs:range xsd:integer ;
                         bsfs:unique "true"^^xsd:boolean .
                     ''',
                 'tuples': [
-                    ('http://bsfs.ai/schema/Entity#author', 'Me, myself, and I'),
-                    ('http://bsfs.ai/schema/Entity#rating', 123),
+                    ('https://schema.bsfs.io/ie/Node/Entity#author', 'Me, myself, and I'),
+                    ('https://schema.bsfs.io/ie/Node/Entity#rating', 123),
                     ],
             }}])
         obj = builder.build(0)
         import bsie.extractor.generic.constant
         self.assertEqual(obj, bsie.extractor.generic.constant.Constant('''
                     bse:author rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs:Entity ;
+                        rdfs:domain bsn:Entity ;
                         rdfs:range xsd:string ;
                         bsfs:unique "true"^^xsd:boolean .
                     bse:rating rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs:Entity ;
+                        rdfs:domain bsn:Entity ;
                         rdfs:range xsd:integer ;
                         bsfs:unique "true"^^xsd:boolean .
                     ''', [
-            ('http://bsfs.ai/schema/Entity#author', 'Me, myself, and I'),
-            ('http://bsfs.ai/schema/Entity#rating', 123),
+            ('https://schema.bsfs.io/ie/Node/Entity#author', 'Me, myself, and I'),
+            ('https://schema.bsfs.io/ie/Node/Entity#rating', 123),
             ]))
 
         # building with invalid args
diff --git a/test/extractor/test_preview.py b/test/extractor/test_preview.py
index 10d2a7f..6526783 100644
--- a/test/extractor/test_preview.py
+++ b/test/extractor/test_preview.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # standard imports
 import io
 import os
@@ -45,28 +40,28 @@ class TestPreview(unittest.TestCase):
     def test_schema(self):
         self.assertEqual(Preview([1,2,3]).schema,
             bsfs.schema.from_string(base.SCHEMA_PREAMBLE + '''
-                bsfs:Preview rdfs:subClassOf bsfs:Node .
-                bsfs:BinaryBlob rdfs:subClassOf bsfs:Literal .
-                bsfs:JPEG rdfs:subClassOf bsfs:BinaryBlob .
+                bsn:Preview rdfs:subClassOf bsfs:Node .
+                bsl:BinaryBlob rdfs:subClassOf bsfs:Literal .
+                <https://schema.bsfs.io/ie/Literal/BinaryBlob/JPEG> rdfs:subClassOf bsl:BinaryBlob .
 
                 bse:preview rdfs:subClassOf bsfs:Predicate ;
-                    rdfs:domain bsfs:File ;
-                    rdfs:range bsfs:Preview ;
+                    rdfs:domain bsn:Entity ;
+                    rdfs:range bsn:Preview ;
                     bsfs:unique "false"^^xsd:boolean .
 
                 bsp:width rdfs:subClassOf bsfs:Predicate ;
-                    rdfs:domain bsfs:Preview ;
+                    rdfs:domain bsn:Preview ;
                     rdfs:range xsd:integer ;
                     bsfs:unique "true"^^xsd:boolean .
 
                 bsp:height rdfs:subClassOf bsfs:Predicate ;
-                    rdfs:domain bsfs:Preview ;
+                    rdfs:domain bsn:Preview ;
                     rdfs:range xsd:integer ;
                     bsfs:unique "true"^^xsd:boolean .
 
                 bsp:asset rdfs:subClassOf bsfs:Predicate ;
-                    rdfs:domain bsfs:Preview ;
-                    rdfs:range bsfs:JPEG ;
+                    rdfs:domain bsn:Preview ;
+                    rdfs:range <https://schema.bsfs.io/ie/Literal/BinaryBlob/JPEG> ;
                     bsfs:unique "true"^^xsd:boolean .
 
                 '''))
@@ -74,7 +69,7 @@ class TestPreview(unittest.TestCase):
     def test_extract(self):
         # setup dependents
         rdr = Reader()
-        subject = _node.Node(ns.bsfs.File)
+        subject = _node.Node(ns.bsn.Entity)
         path = os.path.join(os.path.dirname(__file__), 'testimage.jpg')
 
         # setup extractor
@@ -88,7 +83,7 @@ class TestPreview(unittest.TestCase):
         gen(10) # NOTE: consume some image to avoid resource error warning
         # extract a preview
         triples = set(ext.extract(subject, rdr(path), principals))
-        thumbs = {node for node, _, _ in triples if node.node_type == ns.bsfs.Preview}
+        thumbs = {node for node, _, _ in triples if node.node_type == ns.bsn.Preview}
         self.assertEqual(len(thumbs), 1)
         thumb = list(thumbs)[0]
         # test properties
@@ -112,7 +107,7 @@ class TestPreview(unittest.TestCase):
         self.assertEqual(principals, {ext.schema.predicate(ns.bse.preview)})
         # extract a preview
         triples = set(ext.extract(subject, rdr(path), principals))
-        thumbs = {node for node, _, _ in triples if node.node_type == ns.bsfs.Preview}
+        thumbs = {node for node, _, _ in triples if node.node_type == ns.bsn.Preview}
         self.assertEqual(len(thumbs), 2)
         self.assertSetEqual({10, 20}, {
             value for _, pred, value in triples if pred == ext.schema.predicate(ns.bsp.width)})