| 23 | 23 | |
| 24 | 24 | |
| 25 | 25 | class Graph: |
| 26 | """ |
| 27 | A class representing a graph data structure. |
| 28 | |
| 29 | The graph can be initialized with a list of tuples that describe attributes, nodes, and edges. |
| 30 | Each tuple must follow a specific format based on its type (ATTR, NODE, EDGE). |
| 31 | |
| 32 | Parameters: |
| 33 | data (list | None): A list of tuples describing the graph elements. Defaults to None. |
| 34 | |
| 35 | Raises: |
| 36 | TypeError: If the data is not a list or if a graph item is malformed. |
| 37 | ValueError: If an unknown item type is encountered. |
| 38 | """ |
| 26 | 39 | def __init__(self, data: list | None = None): |
| 27 | | pass |
| 40 | # Edge Case: Handle None input by initializing empty collections |
| 41 | if data is None: |
| 42 | self.attrs = {} |
| 43 | self.nodes = [] |
| 44 | self.edges = [] |
| 45 | return |
| 46 | |
| 47 | # Edge Case: Graph data is not a list |
| 48 | if not isinstance(data, list): |
| 49 | raise TypeError("Graph data malformed") |
| 50 | |
| 51 | self.attrs = {} |
| 52 | self.nodes = [] |
| 53 | self.edges = [] |
| 54 | |
| 55 | # Process each item in the data list |
| 56 | for item in data: |
| 57 | # Edge Case: Item is not a tuple or doesn't have at least one element |
| 58 | if not isinstance(item, tuple) or len(item) < 1: |
| 59 | raise TypeError("Graph item malformed") |
| 60 | |
| 61 | item_type = item[0] |
| 62 | |
| 63 | # Edge Case: Unknown item type |
| 64 | if item_type not in (NODE, EDGE, ATTR): |
| 65 | raise ValueError("Unknown item") |
| 66 | |
| 67 | # Process attribute item |
| 68 | if item_type == ATTR: |
| 69 | # Edge Case: Attribute tuple doesn't have exactly 3 elements |
| 70 | if len(item) != 3: |
| 71 | raise TypeError("Graph item malformed") |
| 72 | key, value = item[1], item[2] |
| 73 | self.attrs[key] = value |
| 74 | |
| 75 | # Process node item |
| 76 | elif item_type == NODE: |
| 77 | # Edge Case: Node tuple doesn't have exactly 3 elements |
| 78 | if len(item) != 3: |
| 79 | raise TypeError("Graph item malformed") |
| 80 | name, attrs = item[1], item[2] |
| 81 | # Edge Case: Node attributes is not a dict |
| 82 | if not isinstance(attrs, dict): |
| 83 | raise TypeError("Graph item malformed") |
| 84 | self.nodes.append(Node(name, attrs)) |
| 85 | |
| 86 | # Process edge item |
| 87 | elif item_type == EDGE: |
| 88 | # Edge Case: Edge tuple doesn't have exactly 4 elements |
| 89 | if len(item) != 4: |
| 90 | raise TypeError("Graph item malformed") |
| 91 | src, dst, attrs = item[1], item[2], item[3] |
| 92 | # Edge Case: Edge attributes is not a dict |
| 93 | if not isinstance(attrs, dict): |
| 94 | raise TypeError("Graph item malformed") |
| 95 | self.edges.append(Edge(src, dst, attrs)) |
| 96 | |
| 97 | # Handled Edge Cases: None input, non-list data, non-tuple items, items with insufficient length, unknown item types, |
| 98 | # attribute tuples with wrong length, node tuples with wrong length, node attributes not dict, |
| 99 | # edge tuples with wrong length, edge attributes not dict |