Add unit tests for build from single C file

tests/unit_tests/build_test.py

@@ -0,0 +1,52 @@
+"""Unit tests for 'build' sub-command - specifically for making snapshots
+from single C file."""
+from diffkemp.llvm_ir.single_c_builder import SingleCBuilder
+from diffkemp.diffkemp import run_from_cli
+from diffkemp.utils import get_functions_from_llvm
+import filecmp
+import os
+import yaml
+
+SINGLE_C_FILE_DIR = "kernel/linux-4.18.0-240.el8/tools/build/tests/ex/"
+SINGLE_C_FILE_FILENAME = "b.c"
+
+
+def test_single_c_builder():
+    builder = SingleCBuilder(SINGLE_C_FILE_DIR, SINGLE_C_FILE_FILENAME)
+    assert builder.str() == "single_c_file"
+    assert builder.get_function_list() == ["b"]
+    exp_llvm_file = os.path.abspath(os.path.join(SINGLE_C_FILE_DIR, "b.ll"))
+    assert builder.find_llvm_with_symbol_def("b") == exp_llvm_file
+    assert builder.find_llvm_with_symbol_use("b") == exp_llvm_file
+    builder.finalize()
+
+
+def test_build_single_c_file(monkeypatch, tmp_path):
+    """Testing 'build' sub-command - making snapshot from single c file"""
+    source_dir = os.path.join(SINGLE_C_FILE_DIR, SINGLE_C_FILE_FILENAME)
+    output_dir = str(tmp_path)
+    args = ["diffkemp", "build", source_dir, output_dir]
+    monkeypatch.setattr("sys.argv", args)
+    run_from_cli()
+
+    files = os.listdir(output_dir)
+
+    assert "b.c" in files
+    assert filecmp.cmp(
+        os.path.join(SINGLE_C_FILE_DIR, SINGLE_C_FILE_FILENAME),
+        os.path.join(output_dir, "b.c"),
+    ), "c file in snapshot should be same as the original one"
+
+    assert "b.ll" in files
+    llvm_file_path = os.path.join(output_dir, "b.ll")
+    assert "b" in get_functions_from_llvm([llvm_file_path]), \
+        "function from source file should be also in llvm file"
+
+    assert "snapshot.yaml" in files
+    snapshot_yaml_path = os.path.join(output_dir, "snapshot.yaml")
+    with open(snapshot_yaml_path, "r") as file:
+        snapshot_yaml = yaml.safe_load(file)
+    function_list = [function["name"] for function in snapshot_yaml[0]["list"]]
+    assert "b" in function_list, "function name should be in snapshot.yaml"
+    assert snapshot_yaml[0]["llvm_source_finder"]["kind"] == "single_c_file"
+    assert snapshot_yaml[0]["source_dir"] == os.path.abspath(SINGLE_C_FILE_DIR)