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>
diff --git a/tools/tlc/tests/conftest.py b/tools/tlc/tests/conftest.py
index b8f88b5..155746a 100644
--- a/tools/tlc/tests/conftest.py
+++ b/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 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 @@
 @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