package restructuring: base

* Reader and Extractor to respective reader/extractor modules
* ReaderBuilder to reader module
* ExtractorBuilder to extractor module
* Loading module in utils (safe_load, unpack_name)
* Pipeline and PipelineBuilder to lib module
* errors to utils
* documentation: "standard import" and "external import"

16 files changed, 348 insertions, 282 deletions

diff --git a/test/base/__init__.py b/test/base/__init__.py
deleted file mode 100644
index e69de29..0000000
--- a/test/base/__init__.py
+++ /dev/null
diff --git a/test/extractor/generic/test_path.py b/test/extractor/generic/test_path.py
index 820f402..778ac5a 100644
--- a/test/extractor/generic/test_path.py
+++ b/test/extractor/generic/test_path.py
@@ -4,11 +4,11 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import unittest
 
 # bsie imports
-from bsie.base import extractor
+from bsie.extractor import base
 from bsie.utils import bsfs, node as _node, ns
 
 # objects to test
@@ -29,7 +29,7 @@ class TestPath(unittest.TestCase):
 
     def test_schema(self):
         self.assertEqual(Path().schema,
-            bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+            bsfs.schema.Schema.from_string(base.SCHEMA_PREAMBLE + '''
                 bse:filename rdfs:subClassOf bsfs:Predicate ;
                     rdfs:domain bsfs:File ;
                     rdfs:range xsd:string ;
diff --git a/test/extractor/generic/test_stat.py b/test/extractor/generic/test_stat.py
index 3441438..ff74085 100644
--- a/test/extractor/generic/test_stat.py
+++ b/test/extractor/generic/test_stat.py
@@ -4,12 +4,12 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import os
 import unittest
 
 # bsie imports
-from bsie.base import extractor
+from bsie.extractor import base
 from bsie.utils import bsfs, node as _node, ns
 
 # objects to test
@@ -30,7 +30,7 @@ class TestStat(unittest.TestCase):
 
     def test_schema(self):
         self.assertEqual(Stat().schema,
-            bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+            bsfs.schema.Schema.from_string(base.SCHEMA_PREAMBLE + '''
                 bse:filesize rdfs:subClassOf bsfs:Predicate ;
                     rdfs:domain bsfs:File ;
                     rdfs:range xsd:integer ;
diff --git a/test/base/test_extractor.py b/test/extractor/test_base.py
index 30974ef..6a63c59 100644
--- a/test/base/test_extractor.py
+++ b/test/extractor/test_base.py
@@ -4,21 +4,21 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import unittest
 
 # bsie imports
 from bsie.utils import bsfs, ns
 
 # objects to test
-from bsie.base import extractor
+from bsie.extractor import base
 
 
 ## code ##
 
-class StubExtractor(extractor.Extractor):
+class StubExtractor(base.Extractor):
     def __init__(self):
-        super().__init__(bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+        super().__init__(bsfs.schema.Schema.from_string(base.SCHEMA_PREAMBLE + '''
             bse:author rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:Entity ;
                 rdfs:range xsd:string ;
diff --git a/test/extractor/test_builder.py b/test/extractor/test_builder.py
new file mode 100644
index 0000000..039ea53
--- /dev/null
+++ b/test/extractor/test_builder.py
@@ -0,0 +1,103 @@
+"""
+
+Part of the bsie test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# standard imports
+import unittest
+
+# bsie imports
+from bsie.utils import errors
+
+# objects to test
+from bsie.extractor import ExtractorBuilder
+
+
+## code ##
+
+class TestExtractorBuilder(unittest.TestCase):
+    def test_iter(self):
+        # no specifications
+        self.assertListEqual(list(ExtractorBuilder([])), [])
+        # some specifications
+        builder = ExtractorBuilder([
+            {'bsie.extractor.generic.path.Path': {}},
+            {'bsie.extractor.generic.stat.Stat': {}},
+            {'bsie.extractor.generic.path.Path': {}},
+            ])
+        self.assertListEqual(list(builder), [0, 1, 2])
+
+    def test_build(self):
+        # simple and repeated extractors
+        builder = ExtractorBuilder([
+            {'bsie.extractor.generic.path.Path': {}},
+            {'bsie.extractor.generic.stat.Stat': {}},
+            {'bsie.extractor.generic.path.Path': {}},
+            ])
+        ext = [builder.build(0), builder.build(1), builder.build(2)]
+        import bsie.extractor.generic.path
+        import bsie.extractor.generic.stat
+        self.assertListEqual(ext, [
+            bsie.extractor.generic.path.Path(),
+            bsie.extractor.generic.stat.Stat(),
+            bsie.extractor.generic.path.Path(),
+            ])
+        # out-of-bounds raises KeyError
+        self.assertRaises(IndexError, builder.build, 3)
+
+        # building with args
+        builder = ExtractorBuilder([
+            {'bsie.extractor.generic.constant.Constant': {
+                'schema': '''
+                    bse:author rdfs:subClassOf bsfs:Predicate ;
+                        rdfs:domain bsfs:Entity ;
+                        rdfs:range xsd:string ;
+                        bsfs:unique "true"^^xsd:boolean .
+                    bse:rating rdfs:subClassOf bsfs:Predicate ;
+                        rdfs:domain bsfs: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),
+                    ],
+            }}])
+        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:range xsd:string ;
+                        bsfs:unique "true"^^xsd:boolean .
+                    bse:rating rdfs:subClassOf bsfs:Predicate ;
+                        rdfs:domain bsfs: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),
+            ]))
+
+        # building with invalid args
+        self.assertRaises(errors.BuilderError, ExtractorBuilder(
+            [{'bsie.extractor.generic.path.Path': {'foo': 123}}]).build, 0)
+        # non-dict build specification
+        self.assertRaises(TypeError, ExtractorBuilder(
+            [('bsie.extractor.generic.path.Path', {})]).build, 0)
+        # multiple keys per build specification
+        self.assertRaises(TypeError, ExtractorBuilder(
+            [{'bsie.extractor.generic.path.Path': {},
+              'bsie.extractor.generic.stat.Stat': {}}]).build, 0)
+        # non-dict value for kwargs
+        self.assertRaises(TypeError, ExtractorBuilder(
+            [{'bsie.extractor.generic.path.Path': 123}]).build, 0)
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/lib/test_bsie.py b/test/lib/test_bsie.py
index 771a0c2..52f1d44 100644
--- a/test/lib/test_bsie.py
+++ b/test/lib/test_bsie.py
@@ -4,13 +4,15 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import os
 import unittest
 
 # bsie imports
-from bsie.base import extractor
-from bsie.tools import builder
+from bsie.extractor import ExtractorBuilder
+from bsie.extractor.base import SCHEMA_PREAMBLE
+from bsie.lib import PipelineBuilder
+from bsie.reader import ReaderBuilder
 from bsie.utils import bsfs, node, ns
 
 # objects to test
@@ -22,9 +24,9 @@ from bsie.lib.bsie import BSIE
 class TestBSIE(unittest.TestCase):
     def setUp(self):
         # reader builder
-        rbuild = builder.ReaderBuilder({})
+        rbuild = ReaderBuilder({})
         # extractor builder
-        ebuild = builder.ExtractorBuilder([
+        ebuild = ExtractorBuilder([
             {'bsie.extractor.generic.path.Path': {}},
             {'bsie.extractor.generic.stat.Stat': {}},
             {'bsie.extractor.generic.constant.Constant': dict(
@@ -39,7 +41,7 @@ class TestBSIE(unittest.TestCase):
             ])
         # build pipeline
         self.prefix = bsfs.Namespace('http://example.com/local/')
-        pbuild = builder.PipelineBuilder(self.prefix, rbuild, ebuild)
+        pbuild = PipelineBuilder(self.prefix, rbuild, ebuild)
         self.pipeline = pbuild.build()
 
     def test_construction(self):
@@ -50,7 +52,7 @@ class TestBSIE(unittest.TestCase):
             ns.bse.filesize,
             ns.bse.author,
             })
-        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(SCHEMA_PREAMBLE + '''
             bse:filename rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:File ;
                 rdfs:range xsd:string ;
@@ -77,7 +79,7 @@ class TestBSIE(unittest.TestCase):
             ns.bse.filesize,
             ns.bse.author,
             })
-        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(SCHEMA_PREAMBLE + '''
             bse:filesize rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:File ;
                 rdfs:range xsd:integer;
@@ -95,7 +97,7 @@ class TestBSIE(unittest.TestCase):
             ns.bse.filesize,
             ns.bse.author,
             })
-        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(SCHEMA_PREAMBLE + '''
             bse:filename rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:File ;
                 rdfs:range xsd:string ;
@@ -122,7 +124,7 @@ class TestBSIE(unittest.TestCase):
         self.assertSetEqual(set(lib.principals), {
             ns.bse.author,
             })
-        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(SCHEMA_PREAMBLE + '''
             bse:author rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:Entity ;
                 rdfs:range xsd:string ;
@@ -137,7 +139,7 @@ class TestBSIE(unittest.TestCase):
         self.assertSetEqual(set(lib.principals), {
             ns.bse.filesize,
             })
-        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+        self.assertEqual(lib.schema, bsfs.schema.Schema.from_string(SCHEMA_PREAMBLE + '''
             bse:filesize rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:File ;
                 rdfs:range xsd:integer;
diff --git a/test/lib/test_builder.py b/test/lib/test_builder.py
new file mode 100644
index 0000000..273d620
--- /dev/null
+++ b/test/lib/test_builder.py
@@ -0,0 +1,107 @@
+"""
+
+Part of the bsie test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# standard imports
+import logging
+import unittest
+
+# bsie imports
+from bsie.extractor import ExtractorBuilder
+from bsie.reader import ReaderBuilder
+from bsie.utils import bsfs
+
+# objects to test
+from bsie.lib import PipelineBuilder
+
+
+## code ##
+
+class TestPipelineBuilder(unittest.TestCase):
+    def test_build(self):
+        prefix = bsfs.URI('http://example.com/local/file#')
+        c_schema = '''
+            bse:author rdfs:subClassOf bsfs:Predicate ;
+                rdfs:domain bsfs:Entity ;
+                rdfs:range xsd:string ;
+                bsfs:unique "true"^^xsd:boolean .
+            '''
+        c_tuples = [('http://bsfs.ai/schema/Entity#author', 'Me, myself, and I')]
+        # prepare builders
+        rbuild = ReaderBuilder({})
+        ebuild = ExtractorBuilder([
+            {'bsie.extractor.generic.path.Path': {}},
+            {'bsie.extractor.generic.stat.Stat': {}},
+            {'bsie.extractor.generic.constant.Constant': dict(
+                schema=c_schema,
+                tuples=c_tuples,
+                )},
+            ])
+        # build pipeline
+        builder = PipelineBuilder(prefix, rbuild, ebuild)
+        pipeline = builder.build()
+        # delayed import
+        import bsie.reader.path
+        import bsie.reader.stat
+        import bsie.extractor.generic.path
+        import bsie.extractor.generic.stat
+        import bsie.extractor.generic.constant
+        # check pipeline
+        self.assertDictEqual(pipeline._ext2rdr, {
+            bsie.extractor.generic.path.Path(): bsie.reader.path.Path(),
+            bsie.extractor.generic.stat.Stat(): bsie.reader.stat.Stat(),
+            bsie.extractor.generic.constant.Constant(c_schema, c_tuples): None,
+            })
+
+        # fail to load extractor
+        ebuild_err = ExtractorBuilder([
+            {'bsie.extractor.generic.foo.Foo': {}},
+            {'bsie.extractor.generic.path.Path': {}},
+            ])
+        with self.assertLogs(logging.getLogger('bsie.lib.builder'), logging.ERROR):
+            pipeline = PipelineBuilder(prefix, rbuild, ebuild_err).build()
+            self.assertDictEqual(pipeline._ext2rdr, {
+                bsie.extractor.generic.path.Path(): bsie.reader.path.Path()})
+
+        # fail to build extractor
+        ebuild_err = ExtractorBuilder([
+            {'bsie.extractor.generic.path.Path': {'foo': 123}},
+            {'bsie.extractor.generic.path.Path': {}},
+            ])
+        with self.assertLogs(logging.getLogger('bsie.lib.builder'), logging.ERROR):
+            pipeline = PipelineBuilder(prefix, rbuild, ebuild_err).build()
+            self.assertDictEqual(pipeline._ext2rdr, {
+                bsie.extractor.generic.path.Path(): bsie.reader.path.Path()})
+
+        # fail to load reader
+        with self.assertLogs(logging.getLogger('bsie.lib.builder'), logging.ERROR):
+            # switch reader of an extractor
+            old_reader = bsie.extractor.generic.path.Path.CONTENT_READER
+            bsie.extractor.generic.path.Path.CONTENT_READER = 'bsie.reader.foo.Foo'
+            # build pipeline with invalid reader reference
+            pipeline = PipelineBuilder(prefix, rbuild, ebuild).build()
+            self.assertDictEqual(pipeline._ext2rdr, {
+                bsie.extractor.generic.stat.Stat(): bsie.reader.stat.Stat(),
+                bsie.extractor.generic.constant.Constant(c_schema, c_tuples): None,
+                })
+            # switch back
+            bsie.extractor.generic.path.Path.CONTENT_READER = old_reader
+
+        # fail to build reader
+        rbuild_err = ReaderBuilder({'bsie.reader.stat.Stat': dict(foo=123)})
+        with self.assertLogs(logging.getLogger('bsie.lib.builder'), logging.ERROR):
+            pipeline = PipelineBuilder(prefix, rbuild_err, ebuild).build()
+            self.assertDictEqual(pipeline._ext2rdr, {
+                bsie.extractor.generic.path.Path(): bsie.reader.path.Path(),
+                bsie.extractor.generic.constant.Constant(c_schema, c_tuples): None,
+                })
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/tools/test_pipeline.py b/test/lib/test_pipeline.py
index a116a30..c6f7aba 100644
--- a/test/tools/test_pipeline.py
+++ b/test/lib/test_pipeline.py
@@ -4,14 +4,13 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import logging
 import os
 import unittest
 
 # bsie imports
-from bsie.base import errors
-from bsie.utils import bsfs, node, ns
+from bsie.utils import bsfs, errors, node, ns
 import bsie.extractor.generic.constant
 import bsie.extractor.generic.path
 import bsie.extractor.generic.stat
@@ -19,7 +18,7 @@ import bsie.reader.path
 import bsie.reader.stat
 
 # objects to test
-from bsie.tools.pipeline import Pipeline
+from bsie.lib.pipeline import Pipeline
 
 
 ## code ##
@@ -140,7 +139,7 @@ class TestPipeline(unittest.TestCase):
                 raise errors.ReaderError('reader error')
 
         pipeline = Pipeline(self.prefix, {bsie.extractor.generic.path.Path(): FaultyReader()})
-        with self.assertLogs(logging.getLogger('bsie.tools.pipeline'), logging.ERROR):
+        with self.assertLogs(logging.getLogger('bsie.lib.pipeline'), logging.ERROR):
             testfile = os.path.join(os.path.dirname(__file__), 'testfile.t')
             p_filename = pipeline.schema.predicate(ns.bse.filename)
             self.assertSetEqual(set(pipeline(testfile, {p_filename})), set())
@@ -151,7 +150,7 @@ class TestPipeline(unittest.TestCase):
                 raise errors.ExtractorError('extractor error')
 
         pipeline = Pipeline(self.prefix, {FaultyExtractor(): bsie.reader.path.Path()})
-        with self.assertLogs(logging.getLogger('bsie.tools.pipeline'), logging.ERROR):
+        with self.assertLogs(logging.getLogger('bsie.lib.pipeline'), logging.ERROR):
             testfile = os.path.join(os.path.dirname(__file__), 'testfile.t')
             p_filename = pipeline.schema.predicate(ns.bse.filename)
             self.assertSetEqual(set(pipeline(testfile, {p_filename})), set())
diff --git a/test/base/test_reader.py b/test/reader/test_base.py
index a907eb9..41f4c29 100644
--- a/test/base/test_reader.py
+++ b/test/reader/test_base.py
@@ -4,16 +4,16 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import unittest
 
 # objects to test
-from bsie import base
+from bsie.reader import Reader
 
 
 ## code ##
 
-class StubReader(base.Reader):
+class StubReader(Reader):
     def __call__(self, path):
         raise NotImplementedError()
 
diff --git a/test/reader/test_builder.py b/test/reader/test_builder.py
new file mode 100644
index 0000000..92e9edc
--- /dev/null
+++ b/test/reader/test_builder.py
@@ -0,0 +1,54 @@
+"""
+
+Part of the bsie test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# standard imports
+import unittest
+
+# bsie imports
+from bsie.utils import errors
+
+# objects to test
+from bsie.reader import ReaderBuilder
+
+
+## code ##
+
+class TestReaderBuilder(unittest.TestCase):
+    def test_build(self):
+        builder = ReaderBuilder({'bsie.reader.path.Path': {}})
+        # build configured reader
+        cls = builder.build('bsie.reader.path.Path')
+        import bsie.reader.path
+        self.assertIsInstance(cls, bsie.reader.path.Path)
+        # build unconfigured reader
+        cls = builder.build('bsie.reader.stat.Stat')
+        import bsie.reader.stat
+        self.assertIsInstance(cls, bsie.reader.stat.Stat)
+        # re-build previous reader (test cache)
+        self.assertEqual(cls, builder.build('bsie.reader.stat.Stat'))
+        # test invalid
+        self.assertRaises(TypeError, builder.build, 123)
+        self.assertRaises(TypeError, builder.build, None)
+        self.assertRaises(ValueError, builder.build, '')
+        self.assertRaises(ValueError, builder.build, 'Path')
+        self.assertRaises(errors.BuilderError, builder.build, 'path.Path')
+        # invalid config
+        builder = ReaderBuilder({'bsie.reader.stat.Stat': dict(foo=123)})
+        self.assertRaises(errors.BuilderError, builder.build, 'bsie.reader.stat.Stat')
+        builder = ReaderBuilder({'bsie.reader.stat.Stat': 123})
+        self.assertRaises(TypeError, builder.build, 'bsie.reader.stat.Stat')
+        # no instructions
+        builder = ReaderBuilder({})
+        cls = builder.build('bsie.reader.stat.Stat')
+        self.assertIsInstance(cls, bsie.reader.stat.Stat)
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/reader/test_stat.py b/test/reader/test_stat.py
index d12ad9c..fd9fdcd 100644
--- a/test/reader/test_stat.py
+++ b/test/reader/test_stat.py
@@ -4,12 +4,12 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import os
 import unittest
 
 # bsie imports
-from bsie.base import errors
+from bsie.utils import errors
 
 # objects to test
 from bsie.reader.stat import Stat
diff --git a/test/tools/__init__.py b/test/tools/__init__.py
deleted file mode 100644
index e69de29..0000000
--- a/test/tools/__init__.py
+++ /dev/null
diff --git a/test/tools/test_builder.py b/test/tools/test_builder.py
deleted file mode 100644
index 62c637c..0000000
--- a/test/tools/test_builder.py
+++ /dev/null
@@ -1,246 +0,0 @@
-"""
-
-Part of the bsie test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
-# imports
-import logging
-import unittest
-
-# bsie imports
-from bsie import base
-from bsie.utils import bsfs
-
-# objects to test
-from bsie.tools.builder import ExtractorBuilder
-from bsie.tools.builder import PipelineBuilder
-from bsie.tools.builder import ReaderBuilder
-from bsie.tools.builder import _safe_load
-from bsie.tools.builder import _unpack_name
-
-
-## code ##
-
-class TestUtils(unittest.TestCase):
-    def test_safe_load(self):
-        # invalid module
-        self.assertRaises(base.errors.LoaderError, _safe_load, 'dBGHMSAYOoKeKMpywDoKZQycENFPvN', 'foobar')
-        self.assertRaises(base.errors.LoaderError, _safe_load, 'dBGHMSAYOoKeKMpywDoKZQycENFPvN.bar', 'foobar')
-        # partially valid module
-        self.assertRaises(base.errors.LoaderError, _safe_load, 'os.foo', 'foobar')
-        # invalid class
-        self.assertRaises(base.errors.LoaderError, _safe_load, 'os.path', 'foo')
-        # valid module and class
-        cls = _safe_load('collections.abc', 'Container')
-        import collections.abc
-        self.assertEqual(cls, collections.abc.Container)
-
-    def test_unpack_name(self):
-        self.assertRaises(TypeError, _unpack_name, 123)
-        self.assertRaises(TypeError, _unpack_name, None)
-        self.assertRaises(ValueError, _unpack_name, '')
-        self.assertRaises(ValueError, _unpack_name, 'path')
-        self.assertRaises(ValueError, _unpack_name, '.Path')
-        self.assertEqual(_unpack_name('path.Path'), ('path', 'Path'))
-        self.assertEqual(_unpack_name('path.foo.bar.Path'), ('path.foo.bar', 'Path'))
-
-
-class TestReaderBuilder(unittest.TestCase):
-    def test_build(self):
-        builder = ReaderBuilder({'bsie.reader.path.Path': {}})
-        # build configured reader
-        cls = builder.build('bsie.reader.path.Path')
-        import bsie.reader.path
-        self.assertIsInstance(cls, bsie.reader.path.Path)
-        # build unconfigured reader
-        cls = builder.build('bsie.reader.stat.Stat')
-        import bsie.reader.stat
-        self.assertIsInstance(cls, bsie.reader.stat.Stat)
-        # re-build previous reader (test cache)
-        self.assertEqual(cls, builder.build('bsie.reader.stat.Stat'))
-        # test invalid
-        self.assertRaises(TypeError, builder.build, 123)
-        self.assertRaises(TypeError, builder.build, None)
-        self.assertRaises(ValueError, builder.build, '')
-        self.assertRaises(ValueError, builder.build, 'Path')
-        self.assertRaises(base.errors.BuilderError, builder.build, 'path.Path')
-        # invalid config
-        builder = ReaderBuilder({'bsie.reader.stat.Stat': dict(foo=123)})
-        self.assertRaises(base.errors.BuilderError, builder.build, 'bsie.reader.stat.Stat')
-        builder = ReaderBuilder({'bsie.reader.stat.Stat': 123})
-        self.assertRaises(TypeError, builder.build, 'bsie.reader.stat.Stat')
-        # no instructions
-        builder = ReaderBuilder({})
-        cls = builder.build('bsie.reader.stat.Stat')
-        self.assertIsInstance(cls, bsie.reader.stat.Stat)
-
-
-
-class TestExtractorBuilder(unittest.TestCase):
-    def test_iter(self):
-        # no specifications
-        self.assertListEqual(list(ExtractorBuilder([])), [])
-        # some specifications
-        builder = ExtractorBuilder([
-            {'bsie.extractor.generic.path.Path': {}},
-            {'bsie.extractor.generic.stat.Stat': {}},
-            {'bsie.extractor.generic.path.Path': {}},
-            ])
-        self.assertListEqual(list(builder), [0, 1, 2])
-
-    def test_build(self):
-        # simple and repeated extractors
-        builder = ExtractorBuilder([
-            {'bsie.extractor.generic.path.Path': {}},
-            {'bsie.extractor.generic.stat.Stat': {}},
-            {'bsie.extractor.generic.path.Path': {}},
-            ])
-        ext = [builder.build(0), builder.build(1), builder.build(2)]
-        import bsie.extractor.generic.path
-        import bsie.extractor.generic.stat
-        self.assertListEqual(ext, [
-            bsie.extractor.generic.path.Path(),
-            bsie.extractor.generic.stat.Stat(),
-            bsie.extractor.generic.path.Path(),
-            ])
-        # out-of-bounds raises KeyError
-        self.assertRaises(IndexError, builder.build, 3)
-
-        # building with args
-        builder = ExtractorBuilder([
-            {'bsie.extractor.generic.constant.Constant': {
-                'schema': '''
-                    bse:author rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs:Entity ;
-                        rdfs:range xsd:string ;
-                        bsfs:unique "true"^^xsd:boolean .
-                    bse:rating rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs: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),
-                    ],
-            }}])
-        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:range xsd:string ;
-                        bsfs:unique "true"^^xsd:boolean .
-                    bse:rating rdfs:subClassOf bsfs:Predicate ;
-                        rdfs:domain bsfs: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),
-            ]))
-
-        # building with invalid args
-        self.assertRaises(base.errors.BuilderError, ExtractorBuilder(
-            [{'bsie.extractor.generic.path.Path': {'foo': 123}}]).build, 0)
-        # non-dict build specification
-        self.assertRaises(TypeError, ExtractorBuilder(
-            [('bsie.extractor.generic.path.Path', {})]).build, 0)
-        # multiple keys per build specification
-        self.assertRaises(TypeError, ExtractorBuilder(
-            [{'bsie.extractor.generic.path.Path': {},
-              'bsie.extractor.generic.stat.Stat': {}}]).build, 0)
-        # non-dict value for kwargs
-        self.assertRaises(TypeError, ExtractorBuilder(
-            [{'bsie.extractor.generic.path.Path': 123}]).build, 0)
-
-
-
-
-class TestPipelineBuilder(unittest.TestCase):
-    def test_build(self):
-        prefix = bsfs.URI('http://example.com/local/file#')
-        c_schema = '''
-            bse:author rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range xsd:string ;
-                bsfs:unique "true"^^xsd:boolean .
-            '''
-        c_tuples = [('http://bsfs.ai/schema/Entity#author', 'Me, myself, and I')]
-        # prepare builders
-        rbuild = ReaderBuilder({})
-        ebuild = ExtractorBuilder([
-            {'bsie.extractor.generic.path.Path': {}},
-            {'bsie.extractor.generic.stat.Stat': {}},
-            {'bsie.extractor.generic.constant.Constant': dict(
-                schema=c_schema,
-                tuples=c_tuples,
-                )},
-            ])
-        # build pipeline
-        builder = PipelineBuilder(prefix, rbuild, ebuild)
-        pipeline = builder.build()
-        # delayed import
-        import bsie.reader.path
-        import bsie.reader.stat
-        import bsie.extractor.generic.path
-        import bsie.extractor.generic.stat
-        import bsie.extractor.generic.constant
-        # check pipeline
-        self.assertDictEqual(pipeline._ext2rdr, {
-            bsie.extractor.generic.path.Path(): bsie.reader.path.Path(),
-            bsie.extractor.generic.stat.Stat(): bsie.reader.stat.Stat(),
-            bsie.extractor.generic.constant.Constant(c_schema, c_tuples): None,
-            })
-
-        # fail to load extractor
-        ebuild_err = ExtractorBuilder([
-            {'bsie.extractor.generic.foo.Foo': {}},
-            {'bsie.extractor.generic.path.Path': {}},
-            ])
-        with self.assertLogs(logging.getLogger('bsie.tools.builder'), logging.ERROR):
-            pipeline = PipelineBuilder(prefix, rbuild, ebuild_err).build()
-            self.assertDictEqual(pipeline._ext2rdr, {
-                bsie.extractor.generic.path.Path(): bsie.reader.path.Path()})
-
-        # fail to build extractor
-        ebuild_err = ExtractorBuilder([
-            {'bsie.extractor.generic.path.Path': {'foo': 123}},
-            {'bsie.extractor.generic.path.Path': {}},
-            ])
-        with self.assertLogs(logging.getLogger('bsie.tools.builder'), logging.ERROR):
-            pipeline = PipelineBuilder(prefix, rbuild, ebuild_err).build()
-            self.assertDictEqual(pipeline._ext2rdr, {
-                bsie.extractor.generic.path.Path(): bsie.reader.path.Path()})
-
-        # fail to load reader
-        with self.assertLogs(logging.getLogger('bsie.tools.builder'), logging.ERROR):
-            # switch reader of an extractor
-            old_reader = bsie.extractor.generic.path.Path.CONTENT_READER
-            bsie.extractor.generic.path.Path.CONTENT_READER = 'bsie.reader.foo.Foo'
-            # build pipeline with invalid reader reference
-            pipeline = PipelineBuilder(prefix, rbuild, ebuild).build()
-            self.assertDictEqual(pipeline._ext2rdr, {
-                bsie.extractor.generic.stat.Stat(): bsie.reader.stat.Stat(),
-                bsie.extractor.generic.constant.Constant(c_schema, c_tuples): None,
-                })
-            # switch back
-            bsie.extractor.generic.path.Path.CONTENT_READER = old_reader
-
-        # fail to build reader
-        rbuild_err = ReaderBuilder({'bsie.reader.stat.Stat': dict(foo=123)})
-        with self.assertLogs(logging.getLogger('bsie.tools.builder'), logging.ERROR):
-            pipeline = PipelineBuilder(prefix, rbuild_err, ebuild).build()
-            self.assertDictEqual(pipeline._ext2rdr, {
-                bsie.extractor.generic.path.Path(): bsie.reader.path.Path(),
-                bsie.extractor.generic.constant.Constant(c_schema, c_tuples): None,
-                })
-
-
-## main ##
-
-if __name__ == '__main__':
-    unittest.main()
-
-## EOF ##
diff --git a/test/tools/testfile.t b/test/tools/testfile.t
deleted file mode 100644
index 3b18e51..0000000
--- a/test/tools/testfile.t
+++ /dev/null
@@ -1 +0,0 @@
-hello world
diff --git a/test/utils/filematcher/test_parser.py b/test/utils/filematcher/test_parser.py
index a81d2ed..c594747 100644
--- a/test/utils/filematcher/test_parser.py
+++ b/test/utils/filematcher/test_parser.py
@@ -4,11 +4,11 @@ Part of the bsie test suite.
 A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
-# imports
+# standard imports
 import unittest
 
-# inner-module imports
-from bsie.base import errors
+# bsie imports
+from bsie.utils import errors
 from bsie.utils.filematcher import matcher
 
 # objects to test
diff --git a/test/utils/test_loading.py b/test/utils/test_loading.py
new file mode 100644
index 0000000..58ff166
--- /dev/null
+++ b/test/utils/test_loading.py
@@ -0,0 +1,48 @@
+"""
+
+Part of the bsie test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# standard imports
+import unittest
+
+# bsie imports
+from bsie.utils import errors
+
+# objects to test
+from bsie.utils.loading import safe_load, unpack_qualified_name
+
+
+## code ##
+
+class TestUtils(unittest.TestCase):
+    def test_safe_load(self):
+        # invalid module
+        self.assertRaises(errors.LoaderError, safe_load, 'dBGHMSAYOoKeKMpywDoKZQycENFPvN', 'foobar')
+        self.assertRaises(errors.LoaderError, safe_load, 'dBGHMSAYOoKeKMpywDoKZQycENFPvN.bar', 'foobar')
+        # partially valid module
+        self.assertRaises(errors.LoaderError, safe_load, 'os.foo', 'foobar')
+        # invalid class
+        self.assertRaises(errors.LoaderError, safe_load, 'os.path', 'foo')
+        # valid module and class
+        cls = safe_load('collections.abc', 'Container')
+        import collections.abc
+        self.assertEqual(cls, collections.abc.Container)
+
+    def test_unpack_qualified_name(self):
+        self.assertRaises(TypeError, unpack_qualified_name, 123)
+        self.assertRaises(TypeError, unpack_qualified_name, None)
+        self.assertRaises(ValueError, unpack_qualified_name, '')
+        self.assertRaises(ValueError, unpack_qualified_name, 'path')
+        self.assertRaises(ValueError, unpack_qualified_name, '.Path')
+        self.assertEqual(unpack_qualified_name('path.Path'), ('path', 'Path'))
+        self.assertEqual(unpack_qualified_name('path.foo.bar.Path'), ('path.foo.bar', 'Path'))
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##