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hermetic_build/library_generation/tests/compare_poms.py

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+"""
+Utility to compare the contents of two XML files.
+This focuses on the tree structure of both XML files, meaning that element order and whitespace will be disregarded.
+The only comparison points are: element path (e.g. project/dependencies) and element text
+There is a special case for `dependency`, where the maven coordinates are prepared as well
+"""
+
+from library_generation.utils.utilities import eprint
+import xml.etree.ElementTree as et
+from collections import Counter
+import sys
+import os
+
+current = os.path.dirname(os.path.realpath(__file__))
+parent = os.path.dirname(current)
+sys.path.append(parent)
+
+
+def get_text_from_element(node, element_name, namespace):
+    """
+    Convenience method to access a node's child elements via path and get
+    its text.
+    """
+    child = node.find(namespace + element_name)
+    return child.text if child is not None else ""
+
+
+def print_counter(counter):
+    """
+    Convenience method to pretty print the contents of a Counter (or dict)
+    """
+    for key, value in counter.items():
+        eprint(f"{key}: {value}")
+
+
+def append_to_element_list(node, path, elements):
+    """
+    Recursively traverses a node tree and appends element text to a given
+    `elements` array. If the element tag is `dependency`
+    then the maven coordinates for its children will be computed as well
+    """
+    namespace_start, namespace_end, tag_name = node.tag.rpartition("}")
+    namespace = namespace_start + namespace_end
+    if tag_name == "dependency":
+        group_id = get_text_from_element(node, "groupId", namespace)
+        artifact_id = get_text_from_element(node, "artifactId", namespace)
+        artifact_str = ""
+        artifact_str += group_id
+        artifact_str += ":" + artifact_id
+        elements.append(path + "/" + tag_name + "=" + artifact_str)
+    if node.text and len(node.text.strip()) > 0:
+        elements.append(path + "/" + tag_name + "=" + node.text)
+
+    if tag_name == "version":
+        # versions may be yet to be processed, we disregard them
+        return elements
+
+    for child in node:
+        child_path = path + "/" + tag_name
+        append_to_element_list(child, child_path, elements)
+
+    return elements
+
+
+def compare_xml(expected, actual, print_trees):
+    """
+    compares two XMLs for content differences
+    the argument print_whole_trees determines if both trees should be printed
+    """
+    try:
+        expected_tree = et.parse(expected)
+        actual_tree = et.parse(actual)
+    except et.ParseError as e:
+        eprint(f"Error parsing XML")
+        raise e
+    except FileNotFoundError as e:
+        eprint(f"Error reading file")
+        raise e
+
+    expected_elements = []
+    actual_elements = []
+
+    append_to_element_list(expected_tree.getroot(), "/", expected_elements)
+    append_to_element_list(actual_tree.getroot(), "/", actual_elements)
+
+    expected_counter = Counter(expected_elements)
+    actual_counter = Counter(actual_elements)
+    intersection = expected_counter & actual_counter
+    only_in_expected = expected_counter - intersection
+    only_in_actual = actual_counter - intersection
+    if print_trees:
+        eprint("expected")
+        print_counter(actual_counter)
+        eprint("actual")
+        print_counter(expected_counter)
+    if len(only_in_expected) > 0 or len(only_in_actual) > 0:
+        eprint("only in " + expected)
+        print_counter(only_in_expected)
+        eprint("only in " + actual)
+        print_counter(only_in_actual)
+        return True
+    return False
+
+
+def compare_pom_in_subdir(base_dir: str, subdir: str) -> bool:
+    golden = os.path.join(base_dir, subdir, "pom-golden.xml")
+    pom = os.path.join(base_dir, subdir, "pom.xml")
+    return compare_xml(
+        golden,
+        pom,
+        False,
+    )
+
+
+if __name__ == "__main__":
+    if len(sys.argv) != 4:
+        eprint(
+            "Usage: python compare_xml.py <file1> <file2> <print_whole_trees(true|false)>"
+        )
+        sys.exit(1)
+
+    file1 = sys.argv[1]
+    file2 = sys.argv[2]
+    print_whole_trees = sys.argv[3]
+    has_diff = compare_xml(file1, file2, print_whole_trees)
+
+    if has_diff:
+        eprint(f"The poms are different")
+        sys.exit(1)
+    eprint("The XML files are the same.")
+    sys.exit(0)