diff --git a/py/tests/gen.bin b/py/tests/gen.bin
deleted file mode 100644
index a0f5c55..0000000
Binary files a/py/tests/gen.bin and /dev/null differ
diff --git a/py/tests/test_gen.py b/py/tests/test_gen.py
index 454f5ba..58184ec 100644
--- a/py/tests/test_gen.py
+++ b/py/tests/test_gen.py
@@ -1,73 +1,142 @@
 #!/usr/bin/python3
 
-import difflib
 import io
-import os
 import unittest
 
 import rwmem as rw
 import rwmem.gen as gen
+from rwmem.registerfile import Register, RegisterBlock, RegisterFile
 
-BIN_PATH = os.path.dirname(os.path.abspath(__file__)) + '/gen.bin'
+# Define register blocks without fields
 
-OVR_REGS = [
-    ( 'ATTRIBUTES_0', 0x20, [
+OVR_REGS = (
+    ( 'ATTRIBUTES_0', 0x20 ),
+    ( 'ATTRIBUTES_1', 0x24 ),
+    ( 'ATTRIBUTES_2', 0x28 ),
+    ( 'ATTRIBUTES_3', 0x2c ),
+)
+
+VP_REGS = (
+    ( 'CONTROL', 0x4 ),
+)
+
+BLOCKS = (
+    ( 'VP1', 0x3020a000, 0x1000, VP_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+    ( 'VP2', 0x3020b000, 0x1000, VP_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+    ( 'OVR2', 0x30208000, 0x1000, OVR_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+    ( 'OVR1', 0x30207000, 0x1000, OVR_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+)
+
+# Define register blocks with fields
+
+OVR_REGS_FIELDS = (
+    ( 'ATTRIBUTES_0', 0x20, (
         ( 'POSY', 30, 19 ),
         ( 'POSX', 17, 6 ),
         ( 'CHANNELIN', 4, 1 ),
         ( 'ENABLE', 0, 0 ),
-    ] ),
-    ( 'ATTRIBUTES_1', 0x24, [
+    ) ),
+    ( 'ATTRIBUTES_1', 0x24, (
         ( 'POSY', 30, 19 ),
         ( 'POSX', 17, 6 ),
         ( 'CHANNELIN', 4, 1 ),
         ( 'ENABLE', 0, 0 ),
-    ] ),
-    ( 'ATTRIBUTES_2', 0x28, [
+    ) ),
+    ( 'ATTRIBUTES_2', 0x28, (
         ( 'POSY', 30, 19 ),
         ( 'POSX', 17, 6 ),
         ( 'CHANNELIN', 4, 1 ),
         ( 'ENABLE', 0, 0 ),
-    ] ),
-    ( 'ATTRIBUTES_3', 0x2c, [
+    ) ),
+    ( 'ATTRIBUTES_3', 0x2c, (
         ( 'POSY', 30, 19 ),
         ( 'POSX', 17, 6 ),
         ( 'CHANNELIN', 4, 1 ),
         ( 'ENABLE', 0, 0 ),
-    ] ),
-]
+    ) ),
+)
 
-VP_REGS = [
-    ( 'CONTROL', 0x4, [
+VP_REGS_FIELDS = (
+    ( 'CONTROL', 0x4, (
         ( 'GOBIT', 5, 5 ),
         ( 'ENABLE', 0, 0 ),
-    ] ),
-]
+    ) ),
+)
+
+BLOCKS_FIELDS = (
+    ( 'VP1', 0x3020a000, 0x1000, VP_REGS_FIELDS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+    ( 'VP2', 0x3020b000, 0x1000, VP_REGS_FIELDS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+    ( 'OVR2', 0x30208000, 0x1000, OVR_REGS_FIELDS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+    ( 'OVR1', 0x30207000, 0x1000, OVR_REGS_FIELDS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
+)
 
 class MmapTests(unittest.TestCase):
     def test_gen(self):
-        urf = gen.UnpackedRegFile(
-            'DSS', [
-                ( 'VP1', 0x3020a000, 0x1000, VP_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
-                ( 'VP2', 0x3020b000, 0x1000, VP_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
-                ( 'OVR2', 0x30208000, 0x1000, OVR_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
-                ( 'OVR1', 0x30207000, 0x1000, OVR_REGS, rw.Endianness.Default, 4, rw.Endianness.Default, 4 ),
-            ]
-        )
+        # Create an unpacked register file
+        urf = gen.UnpackedRegFile('DSS', BLOCKS)
 
+        # Pack the unpacked register file into a memory stream.
+        # Normally this would be written to a file.
         with io.BytesIO() as f:
             urf.pack_to(f)
-            data1 = f.getvalue()
+            data = f.getvalue()
+
+        # Create a RegisterFile from the packed data.
+        # Normally this would be read from a file.
+        rf = RegisterFile(data)
+
+        # Test that the register file contains the correct data
+        self.assertEqual(rf.name, 'DSS')
+
+        self.compare_blocks(rf, BLOCKS)
+
+    def test_gen_fields(self):
+        # Create an unpacked register file
+        urf = gen.UnpackedRegFile('DSS', BLOCKS_FIELDS)
+
+        # Pack the unpacked register file into a memory stream.
+        # Normally this would be written to a file.
+        with io.BytesIO() as f:
+            urf.pack_to(f)
+            data = f.getvalue()
+
+        # Create a RegisterFile from the packed data.
+        # Normally this would be read from a file.
+        rf = RegisterFile(data)
+
+        # Test that the register file contains the correct data
+        self.assertEqual(rf.name, 'DSS')
+
+        self.compare_blocks(rf, BLOCKS_FIELDS)
+
+
+    def compare_blocks(self, rf: RegisterFile, ref_blocks):
+        for ref_name, ref_offset, ref_size, ref_regs, ref_ae, ref_as, ref_de, ref_ds in ref_blocks:
+            rb = rf[ref_name]
+            self.assertEqual(rb.name, ref_name)
+            self.assertEqual(rb.offset, ref_offset)
+            self.assertEqual(rb.size, ref_size)
+            self.assertEqual(rb.addr_endianness, ref_ae)
+            self.assertEqual(rb.addr_size, ref_as)
+            self.assertEqual(rb.data_endianness, ref_de)
+            self.assertEqual(rb.data_size, ref_ds)
 
-        with io.FileIO(BIN_PATH, 'r') as f:
-            data2 = f.readall()
+            self.compare_registers(rb, ref_regs)
 
-        s = difflib.SequenceMatcher(None, data1, data2)
+    def compare_registers(self, block: RegisterBlock, ref_regs):
+        for ref_name, ref_offset, *ref_fields in ref_regs:
+            if ref_fields:
+                ref_fields = ref_fields[0]
 
-        ref = ((0, 0, 684), (684, 684, 0))
-        matching = list(s.get_matching_blocks())
+            reg = block[ref_name]
+            self.assertEqual(reg.name, ref_name)
+            self.assertEqual(reg.offset, ref_offset)
 
-        self.assertEqual(len(ref), len(matching))
+            self.compare_fields(reg, ref_fields)
 
-        for i in range(len(matching)):
-            self.assertEqual(ref[i], matching[i])
+    def compare_fields(self, reg: Register, ref_fields):
+        for ref_name, ref_high, ref_low in ref_fields:
+            field = reg[ref_name]
+            self.assertEqual(field.name, ref_name)
+            self.assertEqual(field.high, ref_high)
+            self.assertEqual(field.low, ref_low)