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

- Added a test command-line app.

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

@@ -4,9 +4,9 @@ import spock.lang.Specification
 import org.junit.Rule
 import org.junit.rules.TemporaryFolder
 
-class UnixFileModeTest extends Specification {
+class PosixFileTest extends Specification {
     @Rule TemporaryFolder tmpDir
-    final UnixFileMode file = Platform.get(UnixFileMode.class)
+    final PosixFile file = Platform.get(PosixFile.class)
 
     def "can set mode on a file"() {
         def testFile = tmpDir.newFile("test.txt")

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

@@ -0,0 +1,15 @@
+package net.rubygrapefruit.platform
+
+import org.junit.Rule
+import org.junit.rules.TemporaryFolder
+import spock.lang.Specification
+
+class ProcessTest extends Specification {
+    @Rule TemporaryFolder tmpDir
+    final Process process = Platform.get(Process.class)
+
+    def "can get PID"() {
+        expect:
+        process.getPid() != 0
+    }
+}

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

@@ -0,0 +1,16 @@
+package net.rubygrapefruit.platform
+
+import org.junit.Rule
+import org.junit.rules.TemporaryFolder
+import spock.lang.Specification
+
+class TerminalTest extends Specification {
+    @Rule TemporaryFolder tmpDir
+    final Terminal terminal = Platform.get(Terminal.class)
+
+    def "can check if attached to terminal"() {
+        expect:
+        !terminal.isTerminal(Terminal.Output.Stdout);
+        !terminal.isTerminal(Terminal.Output.Stderr);
+    }
+}