test: 测试证书用例改为重签 Runner 自带程序

Add-Type 编译的程序集没有产品元数据，仍被元数据比对拦截；改用同一程序重签，
签名前后元数据一致，并检查签名者确为临时测试证书。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: margrop

tests/packaging/test-windows-signatures.ps1

@@ -70,35 +70,26 @@ try {
     [System.IO.File]::WriteAllBytes($tamperedPath, $bytes)
     Assert-Rejected '签名后文件被篡改' $paths
 
-    # 测试证书模式：用临时自签名证书模拟 SignPath 测试证书。
-    # 签名前后须为同一文件，并带有产品名和版本，才能通过元数据比对。
-    $unsignedFixture = Join-Path $taskDir 'unsigned.dll'
-    $selfSignedFixture = Join-Path $taskDir 'self-signed.dll'
-    $fixtureSource = @'
-[assembly: System.Reflection.AssemblyProduct("WrongNotebook")]
-[assembly: System.Reflection.AssemblyInformationalVersion("1.0.0")]
-public static class WrongNotebookSigningFixture {}
-'@
-    Add-Type -TypeDefinition $fixtureSource -OutputAssembly $unsignedFixture -OutputType Library
-    Copy-Item -LiteralPath $unsignedFixture -Destination $selfSignedFixture
+    # 用临时自签名证书重签 Runner 自带程序的副本：签名前后的产品元数据一致，只有签名者不同。
+    $selfSignedFixture = Join-Path $taskDir 'self-signed.exe'
+    Copy-Item -LiteralPath $fixture -Destination $selfSignedFixture
     $testCert = New-SelfSignedCertificate -Type CodeSigningCert -Subject 'CN=WrongNotebook Signing Test' -CertStoreLocation Cert:\CurrentUser\My
     try {
         $result = Set-AuthenticodeSignature -LiteralPath $selfSignedFixture -Certificate $testCert
-        if ($null -eq $result.SignerCertificate) { throw '无法生成自签名测试文件' }
+        if ($null -eq $result.SignerCertificate -or (Get-AuthenticodeSignature -LiteralPath $selfSignedFixture).SignerCertificate.Thumbprint -ne $testCert.Thumbprint) {
+            throw '无法生成自签名测试文件'
+        }
     } finally {
         Remove-Item -LiteralPath "Cert:\CurrentUser\My\$($testCert.Thumbprint)" -Force
     }
 
     $paths = New-FixtureSet 'test-certificate'
-    foreach ($name in $names) {
-        Copy-Item -LiteralPath $unsignedFixture -Destination (Join-Path $paths.UnsignedDirectory $name) -Force
-        Copy-Item -LiteralPath $selfSignedFixture -Destination (Join-Path $paths.SignedDirectory $name) -Force
-    }
+    foreach ($name in $names) { Copy-Item -LiteralPath $selfSignedFixture -Destination (Join-Path $paths.SignedDirectory $name) -Force }
     $production = @{ UnsignedDirectory = $paths.UnsignedDirectory; SignedDirectory = $paths.SignedDirectory }
     Assert-Rejected '生产模式拒绝测试证书' $production
     & $verify @paths -TestCertificate
     foreach ($name in $names) {
-        if ((Get-FileHash -LiteralPath (Join-Path $paths.UnsignedDirectory $name)).Hash -ne (Get-FileHash -LiteralPath $unsignedFixture).Hash) {
+        if ((Get-FileHash -LiteralPath (Join-Path $paths.UnsignedDirectory $name)).Hash -ne (Get-FileHash -LiteralPath $fixture).Hash) {
             throw '测试证书模式不得覆盖发布文件'
         }
     }