stdlib: improve tests

libraries/stdlib/test/io/Files.kt

@@ -0,0 +1,62 @@
+package test.io
+
+import org.junit.Test as test
+import java.io.File
+import kotlin.test.assertEquals
+
+class FilesTest {
+    test fun listFilesWithFilter() {
+        val dir = File.createTempFile("temp", System.nanoTime().toString())
+        dir.delete()
+        dir.mkdir()
+
+        File.createTempFile("temp1", ".kt", dir)
+        File.createTempFile("temp2", ".java", dir)
+        File.createTempFile("temp3", ".kt", dir)
+
+        val result = dir.listFiles { it.getName().endsWith(".kt") }
+        assertEquals(2, result!!.size)
+    }
+
+    test fun recurse() {
+        val dir = File.createTempFile("temp", System.nanoTime().toString())
+        dir.delete()
+
+        var totalFiles = 0
+        dir.recurse { totalFiles++ }
+        assertEquals(1, totalFiles)
+
+        dir.mkdir()
+
+        File.createTempFile("temp", "1.kt", dir)
+        File.createTempFile("temp", "2.java", dir)
+
+        val subdir = File(dir, "subdir")
+        subdir.mkdir()
+
+        File(subdir, "3.txt").createNewFile()
+
+        totalFiles = 0
+        dir.recurse { totalFiles++ }
+
+        assertEquals(5, totalFiles)
+
+        if (subdir.setReadable(false)) {
+            // On Windows, we can't make directory not readable, and setReadable() will return false
+
+            totalFiles = 0
+            dir.recurse { totalFiles++ }
+            assertEquals(4, totalFiles)
+        }
+    }
+
+    test fun relativePath() {
+        val file1 = File("src")
+        val file2 = File(file1, "kotlin")
+        val file3 = File("test")
+
+        assertEquals("kotlin", file1.relativePath(file2))
+        assertEquals("", file1.relativePath(file1))
+        assertEquals(file3.canonicalPath, file1.relativePath(file3))
+    }
+}