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Add GraphCharacteristics
Co-Authored-By: Paul Horn <paul.horn@neotechnology.com>
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‎core/src/main/java/org/neo4j/gds/api/GraphCharacteristics.java‎

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/*
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* Copyright (c) "Neo4j"
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* Neo4j Sweden AB [http://neo4j.com]
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*
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* This file is part of Neo4j.
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*
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* Neo4j is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.neo4j.gds.api;
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import org.neo4j.gds.Orientation;
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import org.neo4j.gds.api.schema.Direction;
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import java.util.Objects;
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/**
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* Graph characteristics describe certain capabilities of the graph.
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* <p>
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* Algorithms define the graph characteristics that they require to
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* for correct execution. The execution framework can use both, the
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* graph and the required characteristics to check if the algorithm
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* can be run on the given graph.
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*/
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public final class GraphCharacteristics {
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public static final GraphCharacteristics ALL;
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public static final GraphCharacteristics NONE;
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static {
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ALL = GraphCharacteristics.builder().directed().undirected().inverseIndexed().build();
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NONE = GraphCharacteristics.builder().build();
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}
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private static final int DIRECTED = 1;
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private static final int UNDIRECTED = 1 << 1;
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private static final int INVERSE_INDEXED = 1 << 2;
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// We use a single int value to store the characteristics.
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// Each bit represents a characteristic. Setting / Getting
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// a characteristic is performed by bit-wise Or / And.
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private final int characteristics;
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public static GraphCharacteristics.Builder builder() {
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return new Builder();
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}
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private GraphCharacteristics(int characteristics) {
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this.characteristics = characteristics;
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}
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public boolean isDirected() {
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return (characteristics() & DIRECTED) == DIRECTED;
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}
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public boolean isUndirected() {
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return (characteristics() & UNDIRECTED) == UNDIRECTED;
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}
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public boolean isInverseIndexed() {
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return (characteristics() & INVERSE_INDEXED) == INVERSE_INDEXED;
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}
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private int characteristics() {
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return characteristics;
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}
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@Override
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public String toString() {
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return "GraphCharacteristics{" +
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"isDirected=" + isDirected() +
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", isUndirected=" + isUndirected() +
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", isInverseIndexed=" + isInverseIndexed() +
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'}';
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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GraphCharacteristics that = (GraphCharacteristics) o;
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return characteristics == that.characteristics;
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}
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@Override
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public int hashCode() {
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return Objects.hash(characteristics);
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}
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public static class Builder {
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private int characteristics = 0;
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public Builder directed() {
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this.characteristics |= GraphCharacteristics.DIRECTED;
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return this;
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}
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public Builder undirected() {
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this.characteristics |= GraphCharacteristics.UNDIRECTED;
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return this;
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}
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public Builder inverseIndexed() {
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this.characteristics |= GraphCharacteristics.INVERSE_INDEXED;
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return this;
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}
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public Builder withOrientation(Orientation orientation) {
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switch (orientation) {
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case NATURAL:
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case REVERSE:
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return this.directed();
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case UNDIRECTED:
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return this.undirected();
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default:
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throw new UnsupportedOperationException("Unexpected orientation: " + orientation);
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}
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}
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public Builder withDirection(Direction direction) {
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switch (direction) {
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case DIRECTED:
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return this.directed();
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case UNDIRECTED:
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return this.undirected();
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default:
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throw new UnsupportedOperationException("Unexpected direction: " + direction);
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}
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}
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public GraphCharacteristics build() {
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return new GraphCharacteristics(this.characteristics);
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}
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}
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}

‎core/src/test/java/org/neo4j/gds/api/GraphCharacteristicsTest.java‎

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/*
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* Copyright (c) "Neo4j"
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* Neo4j Sweden AB [http://neo4j.com]
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*
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* This file is part of Neo4j.
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*
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* Neo4j is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.neo4j.gds.api;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.params.ParameterizedTest;
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import org.junit.jupiter.params.provider.Arguments;
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import org.junit.jupiter.params.provider.MethodSource;
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import org.neo4j.gds.Orientation;
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import org.neo4j.gds.api.schema.Direction;
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import java.util.stream.Stream;
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import static org.assertj.core.api.Assertions.assertThat;
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class GraphCharacteristicsTest {
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@Test
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void emptyCharacteristics() {
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var characteristics = GraphCharacteristics.builder().build();
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assertThat(characteristics.isUndirected()).isFalse();
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assertThat(characteristics.isDirected()).isFalse();
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assertThat(characteristics.isInverseIndexed()).isFalse();
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assertThat(characteristics).isEqualTo(GraphCharacteristics.NONE);
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}
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@Test
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void nonEmptyCharacteristics() {
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var characteristics = GraphCharacteristics.builder().directed().build();
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assertThat(characteristics.isDirected()).isTrue();
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assertThat(characteristics.isUndirected()).isFalse();
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assertThat(characteristics.isInverseIndexed()).isFalse();
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characteristics = GraphCharacteristics.builder().directed().undirected().build();
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assertThat(characteristics.isDirected()).isTrue();
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assertThat(characteristics.isUndirected()).isTrue();
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assertThat(characteristics.isInverseIndexed()).isFalse();
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characteristics = GraphCharacteristics.builder().directed().undirected().inverseIndexed().build();
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assertThat(characteristics.isDirected()).isTrue();
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assertThat(characteristics.isUndirected()).isTrue();
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assertThat(characteristics.isInverseIndexed()).isTrue();
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}
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static Stream<Arguments> orientation() {
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return Stream.of(
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Arguments.of(Orientation.NATURAL, GraphCharacteristics.builder().directed().build()),
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Arguments.of(Orientation.REVERSE, GraphCharacteristics.builder().directed().build()),
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Arguments.of(Orientation.UNDIRECTED, GraphCharacteristics.builder().undirected().build())
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);
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}
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@ParameterizedTest
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@MethodSource("orientation")
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void buildFromOrientation(Orientation orientation, GraphCharacteristics expected) {
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var actual = GraphCharacteristics.builder().withOrientation(orientation).build();
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assertThat(actual).isEqualTo(expected);
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}
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static Stream<Arguments> direction() {
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return Stream.of(
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Arguments.of(Direction.DIRECTED, GraphCharacteristics.builder().directed().build()),
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Arguments.of(Direction.UNDIRECTED, GraphCharacteristics.builder().undirected().build())
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);
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}
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@ParameterizedTest
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@MethodSource("direction")
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void buildFromDirection(Direction direction, GraphCharacteristics expected) {
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var actual = GraphCharacteristics.builder().withDirection(direction).build();
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assertThat(actual).isEqualTo(expected);
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}
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}

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