Change abbreviation characters

While ... is valid in Windows, .NET does not recognize this as a valid path.  As a result, tools like msbuild will fail.  After abbreviation, change ... to --- to avoid issues

Also fix tests on Windows
Windows has \ as the path separator character, and a significantly shorter MAX_PATH.  Set the cached path length long enough that a test that doesn't want the path to be shortened passes.
Also replace / with \ on Windows (and vice versa for non-Windows platforms) when comparing paths.

src/main/java/org/jenkinsci/plugins/shortwspath/ShortWsLocator.java

@@ -74,6 +74,8 @@ public FilePath locate(TopLevelItem item, Node node) {
         if (usabeSpace > BUILD_PATH_LENGTH) return null; // There is plenty of room
 
         String itemName = StringUtils.abbreviate(item.getName(), 0, 16);
+        // Replace the ellipsis with dashes to avoid problems with certain build systems
+        itemName = itemName.replace("...", "---");
         final String digest = Util.getDigestOf(item.getFullName()).substring(0, 8);
         FilePath newPath = slave.getWorkspaceRoot().child(itemName + digest);
 

src/test/java/org/jenkinsci/plugins/shortwspath/LocatorTest.java

@@ -41,10 +41,19 @@
 import org.junit.Test;
 import org.jvnet.hudson.test.JenkinsRule;
 import org.jvnet.hudson.test.MockFolder;
+import hudson.Functions;
 
 public class LocatorTest {
 
     @Rule public JenkinsRule j = new JenkinsRule();
+    private String formatPath(String inputPath) {
+        if(Functions.isWindows()) {
+            return inputPath.replace("/", "\\");
+        }
+        else {
+            return inputPath.replace("\\", "/");
+        }
+    }
 
     @Test
     public void doNothingIfThereIsEnoughRoom() throws Exception {
@@ -54,8 +63,11 @@ public void doNothingIfThereIsEnoughRoom() throws Exception {
         FreeStyleProject p = f.createProject(FreeStyleProject.class, "and_a_project_in_it");
         p.setAssignedNode(s);
 
+        // Not enough for anything.
+        setMaxPathLength(s, 4096);
+
         FreeStyleBuild b = p.scheduleBuild2(0).get();
-        assertThat(b.getWorkspace().getRemote(), equalTo(s.getRootPath() + "/workspace/" + p.getFullName()));
+        assertThat(b.getWorkspace().getRemote(), equalTo(formatPath(s.getRootPath() + "/workspace/" + p.getFullName())));
     }
 
     @Test
@@ -70,7 +82,7 @@ public void doNothingIfItWillNotShortenThePath() throws Exception {
         setMaxPathLength(s, 1);
 
         FreeStyleBuild b = p.scheduleBuild2(0).get();
-        assertThat(b.getWorkspace().getRemote(), equalTo(s.getRootPath() + "/workspace/" + p.getFullName()));
+        assertThat(b.getWorkspace().getRemote(), equalTo(formatPath(s.getRootPath() + "/workspace/" + p.getFullName())));
     }
 
     @Test
@@ -86,7 +98,7 @@ public void unwrapFolders() throws Exception {
 
         FreeStyleBuild b = p.scheduleBuild2(0).get();
         String buildWs = b.getWorkspace().getRemote();
-        String wsDir = s.getRootPath() + "/workspace/";
+        String wsDir = formatPath(s.getRootPath() + "/workspace/");
         assertThat(buildWs, startsWith(wsDir + "and_a_pro"));
         assertThat(buildWs, buildWs.length(), equalTo(wsDir.length() + 24));
     }