feat(tlc): formalise random generation of TEs

To facillitate our testing, add some fixtures to make it easier to
generate transfer entry data.

Change-Id: Ieb76e54e69f410f4f7e1b55fc2cff282e592d1a4
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>

tools/tlc/tests/conftest.py

@@ -9,6 +9,8 @@
 
 """ Common configurations and fixtures for test environment."""
 
+from random import randint
+
 import pytest
 import yaml
 from click.testing import CliRunner
@@ -16,6 +18,10 @@ from click.testing import CliRunner
 from tlc.cli import cli
 
 
+def generate_random_bytes(n):
+    return bytes([randint(0, 255) for _ in range(n)])
+
+
 @pytest.fixture
 def tmptlstr(tmpdir):
     return tmpdir.join("tl.bin").strpath
@@ -70,3 +76,20 @@ def tlcrunner(tmptlstr):
 @pytest.fixture
 def tlc_entries(tmpfdt):
     return [(0, "/dev/null"), (1, tmpfdt.strpath), (0x102, tmpfdt.strpath)]
+
+
+@pytest.fixture
+def random_entry():
+    def _random_entry(max_size):
+        return randint(0, 0xFFFFFF), generate_random_bytes(randint(0, max_size))
+
+    return _random_entry
+
+
+@pytest.fixture
+def random_entries(random_entry):
+    def _random_entries(n=5, max_size=0x100):
+        for _ in range(n):
+            yield random_entry(max_size)
+
+    return _random_entries

tools/tlc/tests/test_transfer_list.py

@@ -125,12 +125,13 @@ def test_single_te_transfer_list(tag_id, data, tmpdir):
         assert f.read(te.data_size) == te.data
 
 
-def test_multiple_te_transfer_list(tmpdir):
+def test_write_multiple_tes_to_file(tmpdir, random_entries):
     """Check that we can create a TL with multiple TE's."""
     test_file = tmpdir.join("test_tl_blob.bin")
-    tl = TransferList(0x1000)
+    tl = TransferList(0x4000)
+    _test_entries = random_entries()
 
-    for tag_id, data in test_entries:
+    for tag_id, data in _test_entries:
         tl.add_transfer_entry(tag_id, data)
 
     tl.write_to_file(test_file)
@@ -138,9 +139,9 @@ def test_multiple_te_transfer_list(tmpdir):
     with open(test_file, "rb") as f:
         assert f.read(tl.hdr_size) == tl.header_to_bytes()
         # Ensure that TE's have the correct alignment
-        for tag_id, data in test_entries:
+        for tag_id, data in _test_entries:
-            f.seek(int(math.ceil(f.tell() / 2**tl.alignment) * 2**tl.alignment))
+            f.seek(int(math.ceil(f.tell() / 8) * 8))
-            print(f.tell())
+
             assert int.from_bytes(f.read(3), "little") == tag_id
             assert int.from_bytes(f.read(1), "little") == TransferEntry.hdr_size
             # Make sure the data in the TE matches the data in the original case