[test] Add `download_cli` test and setup fixture

tests/util-pyhmy/test_util.py

@@ -1,10 +1,22 @@
+import shutil
+import os
 import decimal
 import json
+import subprocess
+from pathlib import Path
 
 import pytest
 
 from pyhmy import util
 
+TEMP_DIR = "/tmp/pyhmy-testing/test-util"
+
+
+@pytest.fixture(scope="session", autouse=True)
+def setup():
+    shutil.rmtree(TEMP_DIR, ignore_errors=True)
+    os.makedirs(TEMP_DIR, exist_ok=True)
+
 
 def test_json_load():
     dec = util.json_load('1.1', parse_float=decimal.Decimal)
@@ -20,3 +32,26 @@ def test_json_load():
     }
     loaded_dict = util.json_load(json.dumps(ref_dict))
     assert str(ref_dict) == str(loaded_dict)
+
+
+def test_download_cli():
+    binary_name = "test-util-binary"
+    path = f"{TEMP_DIR}/test_download_cli/{binary_name}"
+    shutil.rmtree(Path(path).parent, ignore_errors=True)
+    os.makedirs(Path(path).parent, exist_ok=True)
+    existing_hmy_path = os.path.join(Path(path).parent, "hmy")
+    Path(existing_hmy_path).touch()
+    existing_hmy_path_mod = os.path.getmtime(existing_hmy_path)
+    assert not os.path.exists(path), "test file is already present"
+    new_path = util.download_cli(path=path, replace=True, verbose=False)
+    assert new_path == os.path.realpath(path)
+    assert os.path.exists(new_path), "file did not download"
+    assert os.path.getmtime(existing_hmy_path) == existing_hmy_path_mod
+    env = os.environ.copy()
+    env.update(util.get_bls_build_variables())
+    proc = subprocess.Popen([new_path, "version"], env=env,
+                            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    out, err = proc.communicate()
+    assert err, "CLI version is suppose to have non-empty stderr"
+    version = err.decode().strip()
+    assert "harmony" in version.lower(), "cli version does not have `harmony` in it. Not harmony binary?"