Fix remaining Windows test issues

testPlatformOptionsCreateNewConsole: this test was meaning to assert that the values are different, not that they're the same. Fix this simple logic issue.
testRunDetached: this test never completed reading the output, because the write fd was kept open and reading never completed. Close the write fd before reading.
testInputSequenceCustomExecutionBody, testInputAsyncSequenceCustomExecutionBody, testRedirectedOutputRedirectToSequence: these tests hit an implementation issue where EOF was not correctly detected, leading to a hang. Change the logic to return nil if an empty buffer is received.

This patch also enables CI tests for Windows.

Author: jakepetroules

.github/workflows/pull_request.yml

@@ -24,7 +24,6 @@ jobs:
           dnf install -y procps
         fi
       windows_swift_versions: '["6.1", "nightly-main"]'
-      windows_build_command: 'swift build'
       enable_macos_checks: true
       macos_xcode_versions: '["16.3"]'
 

Sources/Subprocess/Platforms/Subprocess+Windows.swift

@@ -1014,7 +1014,7 @@ extension FileDescriptor {
                 case .failure(let error):
                     continuation.resume(throwing: error)
                 case .success(let bytes):
-                    continuation.resume(returning: bytes)
+                    continuation.resume(returning: bytes.isEmpty ? nil : bytes)
                 }
             }
         }

Tests/SubprocessTests/SubprocessTests+Windows.swift

@@ -528,7 +528,7 @@ extension SubprocessWindowsTests {
         ).trimmingCharacters(in: .whitespacesAndNewlines)
         // Make sure the child console is different from parent
         #expect(
-            "\(intptr_t(bitPattern: parentConsole))" == differentConsoleValue
+            "\(intptr_t(bitPattern: parentConsole))" != differentConsoleValue
         )
     }
 
@@ -707,13 +707,13 @@ extension SubprocessWindowsTests {
         WaitForSingleObject(processHandle, INFINITE)
 
         // Up to 10 characters because Windows process IDs are DWORDs (UInt32), whose max value is 10 digits.
+        try writeFd.close()
         let data = try await readFd.readUntilEOF(upToLength: 10)
         let resultPID = try #require(
             String(data: data, encoding: .utf8)
         ).trimmingCharacters(in: .whitespacesAndNewlines)
         #expect("\(pid.value)" == resultPID)
         try readFd.close()
-        try writeFd.close()
     }
 }