split-miner/tests/test_refined_dfg.py

# Split Miner - BPMN process discovery from event logs.
# Authors:
#   imacat@mail.imacat.idv.tw (imacat), 2026/3/12
# AI assistance: Claude Code (Anthropic)

# Copyright (c) 2026 imacat.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.  See the License for the specific language governing
# permissions and limitations under the License.
"""Tests for the refined DFG (Definition 6, SM 2.0).

The refined directly-follows relation uses activity lifecycle
(start/end) events: activity ay directly-follows ax iff
ay starts after ax ends with no other end events in between.

Reference:
    Augusto, A., Dumas, M., & La Rosa, M. (2021).
    Automated Discovery of Process Models with True
    Concurrency and Inclusive Choices. Section 3.1,
    Definition 6.
"""
from __future__ import annotations

import unittest

from split_miner.bpmn import Task
from split_miner.refined_dfg import RefinedDirectlyFollowsGraph

S: str = "start"
"""Lifecycle start constant."""
E: str = "end"
"""Lifecycle end constant."""


def _make_tasks(
    *labels: str,
) -> dict[str, Task]:
    """Create Task objects from labels.

    :param labels: The activity labels.
    :return: A dict mapping label to Task.
    """
    return {
        label: Task(label, label)
        for label in labels
    }


def _make_paper_example() -> tuple[
    dict[str, Task],
    RefinedDirectlyFollowsGraph,
]:
    """Build the DFG from the paper's example Lrho_x.

    Four traces with activities A-F, where B/C and
    D/E have overlapping lifecycles:

    Trace 1: As Ae Bs Cs Ce Be Es Ds De Ee Fs Fe
    Trace 2: As Ae Bs Cs Be Ce Es Ds Ee De Fs Fe
    Trace 3: As Ae Cs Bs Be Ce Ds Es De Ee Fs Fe
    Trace 4: As Ae Cs Bs Ce Be Ds Es Ee De Fs Fe

    Expected DFG (Figure 3c): A->B, A->C, B->D, B->E,
    C->D, C->E, D->F, E->F.

    :return: The tasks and the DFG.
    """
    t: dict[str, Task] = _make_tasks(
        "A", "B", "C", "D", "E", "F"
    )
    a: Task = t["A"]
    b: Task = t["B"]
    c: Task = t["C"]
    d: Task = t["D"]
    e: Task = t["E"]
    f: Task = t["F"]

    traces: dict[
        tuple[tuple[Task, str], ...], int
    ] = {
        # Trace 1
        ((a, S), (a, E), (b, S), (c, S),
         (c, E), (b, E), (e, S), (d, S),
         (d, E), (e, E), (f, S), (f, E)): 1,
        # Trace 2
        ((a, S), (a, E), (b, S), (c, S),
         (b, E), (c, E), (e, S), (d, S),
         (e, E), (d, E), (f, S), (f, E)): 1,
        # Trace 3
        ((a, S), (a, E), (c, S), (b, S),
         (b, E), (c, E), (d, S), (e, S),
         (d, E), (e, E), (f, S), (f, E)): 1,
        # Trace 4
        ((a, S), (a, E), (c, S), (b, S),
         (c, E), (b, E), (d, S), (e, S),
         (e, E), (d, E), (f, S), (f, E)): 1,
    }
    dfg: RefinedDirectlyFollowsGraph = (
        RefinedDirectlyFollowsGraph(traces)
    )
    return t, dfg


class TestSequentialTrace(unittest.TestCase):
    """Tests refined DFG with purely sequential traces.

    When activities don't overlap, the refined DFG matches
    the SM 1.0 DFG.
    """

    def setUp(self) -> None:
        """Set up a simple sequential trace.

        Trace: As Ae Bs Be Cs Ce
        Expected: A->B, B->C.

        :return: None.
        """
        self.__tasks: dict[str, Task] = (
            _make_tasks("A", "B", "C")
        )
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        traces: dict[
            tuple[tuple[Task, str], ...], int
        ] = {
            ((a, S), (a, E),
             (b, S), (b, E),
             (c, S), (c, E)): 1,
        }
        self.__dfg: RefinedDirectlyFollowsGraph = (
            RefinedDirectlyFollowsGraph(traces)
        )

    def test_nodes(self) -> None:
        """DFG has 3 nodes (A, B, C).

        :return: None.
        """
        self.assertEqual(len(self.__dfg.nodes), 3)

    def test_edges(self) -> None:
        """DFG has edges A->B and B->C.

        :return: None.
        """
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        self.assertEqual(
            self.__dfg.edges,
            {(a, b), (b, c)},
        )

    def test_sources(self) -> None:
        """Source is A (first activity to start).

        :return: None.
        """
        self.assertEqual(
            self.__dfg.sources,
            {self.__tasks["A"]},
        )

    def test_sinks(self) -> None:
        """Sink is C (last activity to end).

        :return: None.
        """
        self.assertEqual(
            self.__dfg.sinks,
            {self.__tasks["C"]},
        )


class TestOverlappingTrace(unittest.TestCase):
    """Tests refined DFG with overlapping lifecycles.

    When activities overlap, no directly-follows relation
    exists between them.
    """

    def setUp(self) -> None:
        """Set up overlapping and sequential activities.

        Trace: As Bs Ae Be Cs Ce
        A and B overlap.  B ends last.
        Expected: B->C only (not A->C, since A_end
        precedes B_end which is an end event between
        A_end and C_start).

        :return: None.
        """
        self.__tasks: dict[str, Task] = (
            _make_tasks("A", "B", "C")
        )
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        traces: dict[
            tuple[tuple[Task, str], ...], int
        ] = {
            ((a, S), (b, S), (a, E),
             (b, E), (c, S), (c, E)): 1,
        }
        self.__dfg: RefinedDirectlyFollowsGraph = (
            RefinedDirectlyFollowsGraph(traces)
        )

    def test_no_edge_between_overlapping(self) -> None:
        """No A->B or B->A edge (overlapping lifecycles).

        A starts before B, and A ends before B.  But
        A_end(3) > B_start(2), so A does not end before
        B starts.  Similarly B does not end before A
        starts.  So neither direction holds.

        :return: None.
        """
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        self.assertNotIn((a, b), self.__dfg.edges)
        self.assertNotIn((b, a), self.__dfg.edges)

    def test_last_ender_follows_to_next(self) -> None:
        """Only B->C exists (B is the last to end).

        B_end(4) precedes C_start(5) with no end events
        between them.  A_end(3) also precedes C_start(5)
        but B_end(4) is between them, blocking A->C.

        :return: None.
        """
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        self.assertIn((b, c), self.__dfg.edges)

    def test_edge_count(self) -> None:
        """Only 1 edge total.

        :return: None.
        """
        self.assertEqual(len(self.__dfg.edges), 1)


class TestPaperExample(unittest.TestCase):
    """Tests refined DFG on the paper's example Lrho_x.

    Reference: SM 2.0 paper, Section 3.1, Figure 3(c).
    """

    def setUp(self) -> None:
        """Set up the paper's example.

        :return: None.
        """
        self.__tasks: dict[str, Task]
        self.__dfg: RefinedDirectlyFollowsGraph
        self.__tasks, self.__dfg = (
            _make_paper_example()
        )

    def test_nodes(self) -> None:
        """DFG has 6 nodes (A through F).

        :return: None.
        """
        self.assertEqual(len(self.__dfg.nodes), 6)

    def test_edges(self) -> None:
        """DFG has exactly 8 edges per Figure 3(c).

        A->B, A->C, B->D, B->E, C->D, C->E, D->F,
        E->F.

        :return: None.
        """
        t: dict[str, Task] = self.__tasks
        expected: set[tuple[Task, Task]] = {
            (t["A"], t["B"]), (t["A"], t["C"]),
            (t["B"], t["D"]), (t["B"], t["E"]),
            (t["C"], t["D"]), (t["C"], t["E"]),
            (t["D"], t["F"]), (t["E"], t["F"]),
        }
        self.assertEqual(self.__dfg.edges, expected)

    def test_edge_count(self) -> None:
        """DFG has 8 edges.

        :return: None.
        """
        self.assertEqual(len(self.__dfg.edges), 8)

    def test_no_bidirectional_edges(self) -> None:
        """No bidirectional edges exist.

        In the paper's example, overlapping lifecycles
        prevent any bidirectional relations.

        :return: None.
        """
        for src, tgt in self.__dfg.edges:
            self.assertNotIn(
                (tgt, src), self.__dfg.edges,
                f"Bidirectional edge {src}->{tgt} "
                f"and {tgt}->{src}",
            )

    def test_sources(self) -> None:
        """Source is A.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.sources,
            {self.__tasks["A"]},
        )

    def test_sinks(self) -> None:
        """Sink is F.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.sinks,
            {self.__tasks["F"]},
        )

    def test_a_to_b_frequency(self) -> None:
        """A->B occurs in all 4 traces.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.df_frequency(
                self.__tasks["A"],
                self.__tasks["B"],
            ),
            4,
        )

    def test_a_to_c_frequency(self) -> None:
        """A->C occurs in all 4 traces.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.df_frequency(
                self.__tasks["A"],
                self.__tasks["C"],
            ),
            4,
        )

    def test_b_to_d_frequency(self) -> None:
        """B->D occurs in traces 1 and 4.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.df_frequency(
                self.__tasks["B"],
                self.__tasks["D"],
            ),
            2,
        )

    def test_d_to_f_frequency(self) -> None:
        """D->F occurs in traces 2 and 4.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.df_frequency(
                self.__tasks["D"],
                self.__tasks["F"],
            ),
            2,
        )

    def test_e_to_f_frequency(self) -> None:
        """E->F occurs in traces 1 and 3.

        :return: None.
        """
        self.assertEqual(
            self.__dfg.df_frequency(
                self.__tasks["E"],
                self.__tasks["F"],
            ),
            2,
        )


class TestForkAfterEnd(unittest.TestCase):
    """Tests that multiple activities can follow one end.

    When A ends and both B and C start (with no other end
    events between), both A->B and A->C should exist.
    """

    def setUp(self) -> None:
        """Set up a fork pattern.

        Trace: As Ae Bs Cs Be Ce
        A ends, then B and C start (neither ends before
        the other starts).
        Expected: A->B, A->C.

        :return: None.
        """
        self.__tasks: dict[str, Task] = (
            _make_tasks("A", "B", "C")
        )
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        traces: dict[
            tuple[tuple[Task, str], ...], int
        ] = {
            ((a, S), (a, E), (b, S), (c, S),
             (b, E), (c, E)): 1,
        }
        self.__dfg: RefinedDirectlyFollowsGraph = (
            RefinedDirectlyFollowsGraph(traces)
        )

    def test_fork_edges(self) -> None:
        """Both A->B and A->C exist.

        A_end precedes both B_start and C_start with no
        end events in between.

        :return: None.
        """
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        self.assertEqual(
            self.__dfg.edges,
            {(a, b), (a, c)},
        )


class TestSelfLoop(unittest.TestCase):
    """Tests self-loop detection from lifecycle traces.

    An activity that completes more than once in a trace
    is a self-loop.
    """

    def setUp(self) -> None:
        """Set up trace with self-loop: A repeats.

        Trace: As Ae Bs Be As Ae Cs Ce
        Activity A completes twice.

        :return: None.
        """
        self.__tasks: dict[str, Task] = (
            _make_tasks("A", "B", "C")
        )
        a: Task = self.__tasks["A"]
        b: Task = self.__tasks["B"]
        c: Task = self.__tasks["C"]
        traces: dict[
            tuple[tuple[Task, str], ...], int
        ] = {
            ((a, S), (a, E),
             (b, S), (b, E),
             (a, S), (a, E),
             (c, S), (c, E)): 1,
        }
        self.__dfg: RefinedDirectlyFollowsGraph = (
            RefinedDirectlyFollowsGraph(traces)
        )

    def test_a_is_self_loop(self) -> None:
        """A is detected as a self-loop.

        :return: None.
        """
        self.assertIn(
            self.__tasks["A"],
            self.__dfg.self_loops,
        )

    def test_b_not_self_loop(self) -> None:
        """B is not a self-loop.

        :return: None.
        """
        self.assertNotIn(
            self.__tasks["B"],
            self.__dfg.self_loops,
        )

    def test_no_self_loop_in_paper(self) -> None:
        """Paper example has no self-loops.

        :return: None.
        """
        _, dfg = _make_paper_example()
        self.assertEqual(dfg.self_loops, set())


if __name__ == "__main__":
    unittest.main()