- Added Process.getPid() and Terminal.isTerminal().

- Added a test command-line app.

src/test/groovy/net/rubygrapefruit/platform/PosixFileTest.groovy

@@ -0,0 +1,52 @@
+package net.rubygrapefruit.platform
+
+import spock.lang.Specification
+import org.junit.Rule
+import org.junit.rules.TemporaryFolder
+
+class PosixFileTest extends Specification {
+    @Rule TemporaryFolder tmpDir
+    final PosixFile file = Platform.get(PosixFile.class)
+
+    def "can set mode on a file"() {
+        def testFile = tmpDir.newFile("test.txt")
+
+        when:
+        file.setMode(testFile, 0740)
+
+        then:
+        file.getMode(testFile) == 0740
+    }
+
+    def "can set mode on a file with unicode in its name"() {
+        def testFile = tmpDir.newFile("test\u03b1.txt")
+
+        when:
+        file.setMode(testFile, 0740)
+
+        then:
+        file.getMode(testFile) == 0740
+    }
+
+    def "throws exception on failure to set mode"() {
+        def file = new File(tmpDir.root, "unknown")
+
+        when:
+        this.file.setMode(file, 0660)
+
+        then:
+        NativeException e = thrown()
+        e.message == "Could not set UNIX mode on $file. Errno is 2."
+    }
+
+    def "throws exception on failure to get mode"() {
+        def file = new File(tmpDir.root, "unknown")
+
+        when:
+        this.file.getMode(file)
+
+        then:
+        NativeException e = thrown()
+        e.message == "Could not get UNIX mode on $file. Errno is 2."
+    }
+}