[Workspace] Add lookup() to DependencyManifests

Author: aciidgh

Sources/Commands/Workspace.swift

@@ -176,6 +176,11 @@ public class Workspace {
             return requiredURLs.subtracting(availableURLs)
         }
 
+        /// Find a manifest given its name.
+        func lookup(_ name: String) -> Manifest? {
+            return dependencies.first(where: { $0.name == name })
+        }
+
         init(root: Manifest, dependencies: [Manifest]) {
             self.root = root
             self.dependencies = dependencies

Tests/CommandsTests/WorkspaceTests.swift

@@ -159,17 +159,13 @@ final class WorkspaceTests: XCTestCase {
             XCTAssertEqual(manifests.root.package, graph.rootManifest.package)
             // B should be missing.
             XCTAssertEqual(manifests.missingURLs(), ["//B"])
-            var dependencyManifests: [String: Manifest] = [:]
-            for manifest in manifests.dependencies {
-                dependencyManifests[manifest.package.name] = manifest
-            }
-            XCTAssertEqual(dependencyManifests.keys.sorted(), ["A", "AA"])
+            XCTAssertEqual(manifests.dependencies.map{$0.name}.sorted(), ["A", "AA"])
             let aManifest = graph.manifest("A", version: v1)
-            XCTAssertEqual(dependencyManifests["A"]?.package, aManifest.package)
-            XCTAssertEqual(dependencyManifests["A"]?.version, aManifest.version)
+            XCTAssertEqual(manifests.lookup("A")?.package, aManifest.package)
+            XCTAssertEqual(manifests.lookup("A")?.version, aManifest.version)
             let aaManifest = graph.manifest("AA", version: v1)
-            XCTAssertEqual(dependencyManifests["AA"]?.package, aaManifest.package)
-            XCTAssertEqual(dependencyManifests["AA"]?.version, aaManifest.version)
+            XCTAssertEqual(manifests.lookup("AA")?.package, aaManifest.package)
+            XCTAssertEqual(manifests.lookup("AA")?.version, aaManifest.version)
         }
     }