Add captureStream(…) to observe stdout & stderr in tests.

Signed-off-by: Ross Goldberg <484615+rgoldberg@users.noreply.github.com>

Sources/mas/Formatters/Utilities.swift

@@ -13,63 +13,6 @@ import Foundation
 /// Terminal Control Sequence Indicator
 let csi = "\u{001B}["
 
-#if DEBUG
-
-    var printObserver: ((String) -> Void)?
-
-    // Override global print for testability.
-    // See masTests/OutputListener.swift.
-    func print(
-        _ items: Any...,
-        separator: String = " ",
-        terminator: String = "\n"
-    ) {
-        if let observer = printObserver {
-            let output =
-                items
-                .map { "\($0)" }
-                .joined(separator: separator)
-                .appending(terminator)
-            observer(output)
-        }
-
-        var prefix = ""
-        for item in items {
-            Swift.print(prefix, terminator: "")
-            Swift.print(item, terminator: "")
-            prefix = separator
-        }
-
-        Swift.print(terminator, terminator: "")
-    }
-
-    func print(
-        _ items: Any...,
-        separator: String = " ",
-        terminator: String = "\n",
-        to output: inout some TextOutputStream
-    ) {
-        if let observer = printObserver {
-            let output =
-                items
-                .map { "\($0)" }
-                .joined(separator: separator)
-                .appending(terminator)
-            observer(output)
-        }
-
-        var prefix = ""
-        for item in items {
-            Swift.print(prefix, terminator: "", to: &output)
-            Swift.print(item, terminator: "", to: &output)
-            prefix = separator
-        }
-
-        Swift.print(terminator, terminator: "", to: &output)
-    }
-
-#endif
-
 private var standardError = FileHandle.standardError
 
 extension FileHandle: TextOutputStream {
@@ -121,3 +64,30 @@ func clearLine() {
     print("\(csi)2K\(csi)0G", terminator: "")
     fflush(stdout)
 }
+
+func captureStream(
+    _ stream: UnsafeMutablePointer<FILE>,
+    encoding: String.Encoding = .utf8,
+    _ block: @escaping () throws -> Void
+) throws -> String {
+    let originalFd = fileno(stream)
+    let duplicateFd = dup(originalFd)
+    defer {
+        close(duplicateFd)
+    }
+
+    let pipe = Pipe()
+    dup2(pipe.fileHandleForWriting.fileDescriptor, originalFd)
+
+    do {
+        defer {
+            fflush(stream)
+            dup2(duplicateFd, originalFd)
+            pipe.fileHandleForWriting.closeFile()
+        }
+
+        try block()
+    }
+
+    return String(data: pipe.fileHandleForReading.readDataToEndOfFile(), encoding: encoding) ?? ""
+}

Tests/masTests/Commands/InfoSpec.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2018 mas-cli. All rights reserved.
 //
 
+import Foundation
 import Nimble
 import Quick
 
@@ -47,12 +48,12 @@ public class InfoSpec: QuickSpec {
                     version: "1.0"
                 )
                 storeSearch.apps[mockResult.trackId] = mockResult
-                let output = OutputListener()
                 expect {
+                    try captureStream(stdout) {
                         try Mas.Info.parse([String(mockResult.trackId)]).run(storeSearch: storeSearch)
                     }
-                .toNot(throwError())
+                }
-                expect(output.contents) == """
+                    == """
                     Awesome App 1.0 [2.0]
                     By: Awesome Dev
                     Released: 2019-01-07

Tests/masTests/Commands/ListSpec.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2018 mas-cli. All rights reserved.
 //
 
+import Foundation
 import Nimble
 import Quick
 
@@ -19,9 +20,11 @@ public class ListSpec: QuickSpec {
         describe("list command") {
             it("lists apps") {
                 expect {
+                    try captureStream(stderr) {
                         try Mas.List.parse([]).run(appLibrary: AppLibraryMock())
                     }
-                .toNot(throwError())
+                }
+                    == "Error: No installed apps found\n"
             }
         }
     }

Tests/masTests/Commands/OutdatedSpec.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2018 mas-cli. All rights reserved.
 //
 
+import Foundation
 import Nimble
 import Quick
 
@@ -18,10 +19,39 @@ public class OutdatedSpec: QuickSpec {
         }
         describe("outdated command") {
             it("displays apps with pending updates") {
+                let mockSearchResult =
+                    SearchResult(
+                        bundleId: "au.id.haroldchu.mac.Bandwidth",
+                        currentVersionReleaseDate: "2024-09-02T00:27:00Z",
+                        fileSizeBytes: "998130",
+                        minimumOsVersion: "10.13",
+                        price: 0,
+                        sellerName: "Harold Chu",
+                        sellerUrl: "https://example.com",
+                        trackId: 490_461_369,
+                        trackName: "Bandwidth+",
+                        trackViewUrl: "https://apps.apple.com/us/app/bandwidth/id490461369?mt=12&uo=4",
+                        version: "1.28"
+                    )
+                let mockStoreSearch = StoreSearchMock()
+                mockStoreSearch.apps[mockSearchResult.trackId] = mockSearchResult
+
+                let mockAppLibrary = AppLibraryMock()
+                mockAppLibrary.installedApps.append(
+                    SoftwareProductMock(
+                        appName: mockSearchResult.trackName,
+                        bundleIdentifier: mockSearchResult.bundleId,
+                        bundlePath: "/Applications/Bandwidth+.app",
+                        bundleVersion: "1.27",
+                        itemIdentifier: NSNumber(value: mockSearchResult.trackId)
+                    )
+                )
                 expect {
-                    try Mas.Outdated.parse([]).run(appLibrary: AppLibraryMock(), storeSearch: StoreSearchMock())
+                    try captureStream(stdout) {
+                        try Mas.Outdated.parse([]).run(appLibrary: mockAppLibrary, storeSearch: mockStoreSearch)
                     }
-                .toNot(throwError())
+                }
+                    == "490461369 Bandwidth+ (1.27 -> 1.28)\n"
             }
         }
     }

Tests/masTests/Commands/UninstallSpec.swift

@@ -63,9 +63,11 @@ public class UninstallSpec: QuickSpec {
                 it("removes an app") {
                     mockLibrary.installedApps.append(app)
                     expect {
+                        try captureStream(stdout) {
                             try uninstall.run(appLibrary: mockLibrary)
                         }
-                    .toNot(throwError())
+                    }
+                        == "        1111  slack (0.0)\n==> Some App /tmp/Some.app\n==> (not removed, dry run)\n"
                 }
                 it("fails if there is a problem with the trash command") {
                     var brokenUninstall = app  // make mutable copy

Tests/masTests/Commands/UpgradeSpec.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2018 mas-cli. All rights reserved.
 //
 
+import Foundation
 import Nimble
 import Quick
 
@@ -17,11 +18,14 @@ public class UpgradeSpec: QuickSpec {
             Mas.initialize()
         }
         describe("upgrade command") {
-            it("upgrades stuff") {
+            it("finds no upgrades") {
                 expect {
-                    try Mas.Upgrade.parse([]).run(appLibrary: AppLibraryMock(), storeSearch: StoreSearchMock())
+                    try captureStream(stderr) {
+                        try Mas.Upgrade.parse([])
+                            .run(appLibrary: AppLibraryMock(), storeSearch: StoreSearchMock())
                     }
-                .toNot(throwError())
+                }
+                    == "Warning: Nothing found to upgrade\n"
             }
         }
     }

Tests/masTests/Commands/VersionSpec.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2018 mas-cli. All rights reserved.
 //
 
+import Foundation
 import Nimble
 import Quick
 
@@ -19,9 +20,11 @@ public class VersionSpec: QuickSpec {
         describe("version command") {
             it("displays the current version") {
                 expect {
+                    try captureStream(stdout) {
                         try Mas.Version.parse([]).run()
                     }
-                .toNot(throwError())
+                }
+                    == Package.version + "\n"
             }
         }
     }

Tests/masTests/OutputListener.swift

@@ -1,28 +0,0 @@
-//
-//  OutputListener.swift
-//  masTests
-//
-//  Created by Ben Chatelain on 1/7/19.
-//  Copyright © 2019 mas-cli. All rights reserved.
-//
-
-@testable import mas
-
-/// Test helper for monitoring strings written to stdout. Modified from:
-/// https://stackoverflow.com/a/53569018
-class OutputListener {
-    /// Buffers strings written to stdout
-    var contents = ""
-
-    init() {
-        printObserver = { [weak self] text in
-            strongify(self) { context in
-                context.contents += text
-            }
-        }
-    }
-
-    deinit {
-        printObserver = nil
-    }
-}

Tests/masTests/OutputListenerSpec.swift

@@ -1,39 +0,0 @@
-//
-//  OutputListenerSpec.swift
-//  masTests
-//
-//  Created by Ben Chatelain on 1/8/19.
-//  Copyright © 2019 mas-cli. All rights reserved.
-//
-
-import Nimble
-import Quick
-
-@testable import mas
-
-public class OutputListenerSpec: QuickSpec {
-    override public static func spec() {
-        beforeSuite {
-            Mas.initialize()
-        }
-        describe("output listener") {
-            it("can intercept a single line written stdout") {
-                let output = OutputListener()
-
-                print("hi there", terminator: "")
-
-                expect(output.contents) == "hi there"
-            }
-            it("can intercept multiple lines written stdout") {
-                let output = OutputListener()
-
-                print("hi there")
-
-                expect(output.contents) == """
-                    hi there
-
-                    """
-            }
-        }
-    }
-}

Tests/masTests/Strongify.swift

@@ -1,14 +0,0 @@
-//
-//  Strongify.swift
-//  masTests
-//
-//  Created by Ben Chatelain on 1/8/19.
-//  Copyright © 2019 mas-cli. All rights reserved.
-//
-
-// https://medium.com/@merowing_/stop-weak-strong-dance-in-swift-3aec6d3563d4
-
-func strongify<Context: AnyObject>(_ context: Context?, closure: (Context) -> Void) {
-    guard let strongContext = context else { return }
-    closure(strongContext)
-}