Fix SubprocessStdoutTests on Windows (#3289)

The `echo` command isn't standalone in Windows, so it has to be called
through `cmd.exe` for example.
Interestingly the `echo abc >&2` prints a space at the end of line,
while linux doesnt..

Pull request: #3289

---------

Co-authored-by: Tobias Roeser <le.petit.fou@web.de>

integration/feature/subprocess-stdout/repo/build.sc

@@ -1,18 +1,31 @@
+import scala.util.Properties
 import mill._
 
 
 def inheritInterleaved = T {
   for (i <- Range.inclusive(1, 9)) {
     println("print stdout" + i)
-    os.proc("echo", "proc stdout" + i).call(stdout = os.Inherit)
+    val echoCommandStdout =
+      if (Properties.isWin) Seq("cmd.exe", "/C", s"echo proc stdout${i}")
+      else Seq("echo", s"proc stdout${i}")
+    os.proc(echoCommandStdout).call(stdout = os.Inherit)
     System.err.println("print stderr" + i)
-    os.proc("bash", "-c", s"echo proc stderr${i} >&2").call(stderr = os.Inherit)
+    val echoCommandStderr =
+      if (Properties.isWin) Seq("cmd.exe", "/C", s"echo proc stderr${i}>&2")
+      else Seq("bash", "-c", s"echo proc stderr${i} >&2")
+    os.proc(echoCommandStderr).call(stderr = os.Inherit)
   }
 }
 
 def inheritRaw = T{
   println("print stdoutRaw")
-  os.proc("echo", "proc stdoutRaw").call(stdout = os.InheritRaw)
+  val echoCommandStdoutRaw =
+    if (Properties.isWin) Seq("cmd.exe", "/C", "echo proc stdoutRaw")
+    else Seq("echo", "proc stdoutRaw")
+  os.proc(echoCommandStdoutRaw).call(stdout = os.InheritRaw)
   System.err.println("print stderrRaw")
-  os.proc("bash", "-c", "echo proc stderrRaw >&2").call(stderr = os.InheritRaw)
+  val echoCommandStderrRaw =
+    if (Properties.isWin) Seq("cmd.exe", "/C", "echo proc stderrRaw>&2")
+    else Seq("bash", "-c", "echo proc stderrRaw >&2")
+  os.proc(echoCommandStderrRaw).call(stderr = os.InheritRaw)
 }

integration/feature/subprocess-stdout/test/src/SubprocessStdoutTests.scala

@@ -48,7 +48,7 @@ object SubprocessStdoutTests extends IntegrationTestSuite {
              |print stdout9
              |proc stdout9
              |print stderr9
-             |proc stderr9""".stripMargin
+             |proc stderr9""".stripMargin.replaceAll("\r\n", "\n")
         )
       )
 
@@ -66,7 +66,7 @@ object SubprocessStdoutTests extends IntegrationTestSuite {
             """print stdoutRaw
               |proc stdoutRaw
               |print stderrRaw
-              |proc stderrRaw""".stripMargin
+              |proc stderrRaw""".stripMargin.replaceAll("\r\n", "\n")
           )
         )
       } else {
@@ -77,7 +77,7 @@ object SubprocessStdoutTests extends IntegrationTestSuite {
           """print stdoutRaw
             |print stderrRaw
             |proc stdoutRaw
-            |proc stderrRaw""".stripMargin.linesIterator.toSet.subsetOf(
+            |proc stderrRaw""".stripMargin.replaceAll("\r\n", "\n").linesIterator.toSet.subsetOf(
             res2.linesIterator.toSet
           )
         )