Adding recipe to return minimum JUnit version

src/main/java/org/openrewrite/java/dependencies/search/FindMinimumDependencyVersion.java

@@ -125,6 +125,10 @@ public TreeVisitor<?, ExecutionContext> getVisitor(Map<GroupArtifact, ResolvedGr
 
         acc.entrySet().removeIf(e -> !e.getValue().getVersion().equals(minimumVersion));
 
+        return applyMarkersForLocatedGavs(acc, dependenciesInUse);
+    }
+
+    static TreeVisitor<?, ExecutionContext> applyMarkersForLocatedGavs(Map<GroupArtifact, ResolvedGroupArtifactVersion> acc, DependenciesInUse dependenciesInUse) {
         return Preconditions.check(Preconditions.or(new IsBuildGradle<>(), new FindMavenProject().getVisitor()), new TreeVisitor<Tree, ExecutionContext>() {
             @Override
             public @Nullable Tree visit(@Nullable Tree tree, ExecutionContext ctx) {

src/main/java/org/openrewrite/java/dependencies/search/FindMinimumJUnitVersion.java

@@ -0,0 +1,161 @@
+/*
+ * Copyright 2024 the original author or authors.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.
+ */
+package org.openrewrite.java.dependencies.search;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.jspecify.annotations.Nullable;
+import org.openrewrite.*;
+import org.openrewrite.gradle.marker.GradleDependencyConfiguration;
+import org.openrewrite.gradle.marker.GradleProject;
+import org.openrewrite.internal.StringUtils;
+import org.openrewrite.java.dependencies.internal.StaticVersionComparator;
+import org.openrewrite.java.dependencies.internal.VersionParser;
+import org.openrewrite.marker.Markers;
+import org.openrewrite.maven.table.DependenciesInUse;
+import org.openrewrite.maven.tree.GroupArtifact;
+import org.openrewrite.maven.tree.MavenResolutionResult;
+import org.openrewrite.maven.tree.ResolvedDependency;
+import org.openrewrite.maven.tree.ResolvedGroupArtifactVersion;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import static org.openrewrite.java.dependencies.search.FindMinimumDependencyVersion.applyMarkersForLocatedGavs;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class FindMinimumJUnitVersion extends ScanningRecipe<Map<GroupArtifact, ResolvedGroupArtifactVersion>> {
+    transient DependenciesInUse dependenciesInUse = new DependenciesInUse(this);
+
+    @Option(displayName = "Version",
+            description = "Determine if the provided version is the minimum JUnit version. " +
+                          "If both JUnit 4 and JUnit 5 are present, the minimum version is JUnit 4. " +
+                          "If only one version is present, that version is the minimum version.",
+            example = "4",
+            valid = {"4", "5"},
+            required = false)
+    @Nullable
+    String minimumVersion;
+
+
+    @Override
+    public String getDisplayName() {
+        return "Find minimum JUnit version";
+    }
+
+    @Override
+    public String getDescription() {
+        return "A recipe to find the minimum version of JUnit dependencies. " +
+               "This recipe is designed to return the minimum version of JUnit in a project. " +
+               "It will search for JUnit 4 and JUnit 5 dependencies in the project. " +
+               "If both versions are found, it will return the minimum version of JUnit 4.\n" +
+               "If a minimumVersion is provided, the recipe will search to see if " +
+               "the minimum version of JUnit used by the project is no lower than the minimumVersion.\n" +
+               "For example: if the minimumVersion is 4, and the project has JUnit 4.12 and JUnit 5.7, " +
+               "the recipe will return JUnit 4.12. If the project has only JUnit 5.7, the recipe will return JUnit 5.7.\n" +
+               "Another example: if the minimumVersion is 5, and the project has JUnit 4.12 and JUnit 5.7, " +
+               "the recipe will not return any results.";
+    }
+
+    @Override
+    public Map<GroupArtifact, ResolvedGroupArtifactVersion> getInitialValue(ExecutionContext ctx) {
+        return new HashMap<>();
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getScanner(Map<GroupArtifact, ResolvedGroupArtifactVersion> acc) {
+        return new TreeVisitor<Tree, ExecutionContext>() {
+            @Override
+            public @Nullable Tree visit(@Nullable Tree tree, ExecutionContext ctx) {
+                if (tree == null) {
+                    return null;
+                }
+                VersionParser versionParser = new VersionParser();
+                Markers m = tree.getMarkers();
+                m.findFirst(GradleProject.class).ifPresent(gradle -> {
+                    for (GradleDependencyConfiguration conf : gradle.getConfigurations()) {
+                        collectionJUnit4(versionParser, conf.getResolved(), acc);
+                        collectionJUnit5(versionParser, conf.getResolved(), acc);
+                    }
+                });
+                m.findFirst(MavenResolutionResult.class).ifPresent(maven -> {
+                    for (List<ResolvedDependency> resolved : maven.getDependencies().values()) {
+                        collectionJUnit4(versionParser, resolved, acc);
+                        collectionJUnit5(versionParser, resolved, acc);
+                    }
+                });
+                return tree;
+            }
+        };
+    }
+
+    private boolean isResolvedGroupArtifactVersion(ResolvedGroupArtifactVersion resolvedGroupArtifactVersion, String groupName, String artifactName) {
+        return resolvedGroupArtifactVersion.getArtifactId().equals(artifactName) &&
+               resolvedGroupArtifactVersion.getGroupId().equals(groupName);
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor(Map<GroupArtifact, ResolvedGroupArtifactVersion> acc) {
+        boolean hasJUnit4 = acc.values().stream().anyMatch(resolvedGroupArtifactVersion -> isResolvedGroupArtifactVersion(resolvedGroupArtifactVersion, "junit", "junit"));
+        boolean hasJUnit5 = acc.values().stream().anyMatch(resolvedGroupArtifactVersion -> isResolvedGroupArtifactVersion(resolvedGroupArtifactVersion, "org.junit.jupiter", "junit-jupiter-api"));
+        if (Objects.equals(minimumVersion, "4")) {
+            if (hasJUnit4) {
+                acc.entrySet().removeIf(e -> !isResolvedGroupArtifactVersion(e.getValue(), "junit", "junit"));
+            } else {
+                return TreeVisitor.noop();
+            }
+        } else if (Objects.equals(minimumVersion, "5")) {
+            if (hasJUnit4) {
+                return TreeVisitor.noop();
+            } else {
+                acc.entrySet().removeIf(e -> !isResolvedGroupArtifactVersion(e.getValue(), "org.junit.jupiter", "junit-jupiter-api"));
+            }
+        } else {
+            if (hasJUnit4 && hasJUnit5) {
+                acc.entrySet().removeIf(e -> !isResolvedGroupArtifactVersion(e.getValue(), "junit", "junit"));
+            }
+        }
+
+        return applyMarkersForLocatedGavs(acc, dependenciesInUse);
+    }
+
+    private void collectionJUnit4(VersionParser versionParser, List<ResolvedDependency> resolved,
+                                  Map<GroupArtifact, ResolvedGroupArtifactVersion> acc) {
+        collectVersion(versionParser, resolved, "junit", "junit", acc);
+    }
+
+    private void collectionJUnit5(VersionParser versionParser, List<ResolvedDependency> resolved,
+                                  Map<GroupArtifact, ResolvedGroupArtifactVersion> acc) {
+        collectVersion(versionParser, resolved, "org.junit.jupiter", "junit-jupiter-api", acc);
+    }
+
+    private static void collectVersion(VersionParser versionParser, List<ResolvedDependency> resolved, String groupIdPattern, String artifactIdPattern, Map<GroupArtifact, ResolvedGroupArtifactVersion> acc) {
+        StaticVersionComparator versionComparator = new StaticVersionComparator();
+        for (ResolvedDependency dep : resolved) {
+            if (StringUtils.matchesGlob(dep.getGroupId(), groupIdPattern) &&
+                    StringUtils.matchesGlob(dep.getArtifactId(), artifactIdPattern)) {
+                acc.merge(new GroupArtifact(dep.getGroupId(), dep.getArtifactId()),
+                        dep.getGav(), (d1, d2) -> versionComparator.compare(
+                                versionParser.transform(d1.getVersion()),
+                                versionParser.transform(d2.getVersion())) < 0 ?
+                                d1 : d2);
+            }
+        }
+    }
+}