Add FileUtils tests for SHA1 and deletion (commons-app#2152)

* Add FileUtils tests for SHA1 and deletion

* Avoid changing access modifier for SHA1 test

Author: domdomegg

app/src/test/kotlin/fr/free/nrw/commons/utils/FileUtilsTest.kt

@@ -1,6 +1,7 @@
 package fr.free.nrw.commons.utils
 
 import fr.free.nrw.commons.upload.FileUtils
+import fr.free.nrw.commons.upload.FileUtilsWrapper
 import org.junit.Assert.assertEquals
 import org.junit.Test
 import java.io.*
@@ -17,6 +18,41 @@ class FileUtilsTest {
         assertEquals(getString(source), getString(dest))
     }
 
+    @Test
+    fun deleteFile() {
+        val file = File.createTempFile("testfile", "")
+        writeToFile(file, "Hello, World")
+
+        assertEquals(true, file.exists())
+        assertEquals(true, FileUtils.deleteFile(file))
+        assertEquals(false, file.exists())
+    }
+
+    @Test
+    fun testSHA1() {
+        val fileUtilsWrapper = FileUtilsWrapper()
+
+        assertEquals(
+                "907d14fb3af2b0d4f18c2d46abe8aedce17367bd",
+                fileUtilsWrapper.getSHA1(toInputStream("Hello, World"))
+        )
+
+        assertEquals(
+                "8b971da6347bd126872ea2f4f8d394e70c74073a",
+                fileUtilsWrapper.getSHA1(toInputStream("apps-android-commons"))
+        )
+
+        assertEquals(
+                "e9d30f5a3a82792b9d79c258366bd53207ceaeb3",
+                fileUtilsWrapper.getSHA1(toInputStream("domdomegg was here"))
+        )
+
+        assertEquals(
+                "96e733a3e59261c0621ba99be5bd10bb21abe53e",
+                fileUtilsWrapper.getSHA1(toInputStream("iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII="))
+        )
+    }
+
     private fun writeToFile(file: File, s: String) {
         val buf = BufferedOutputStream(FileOutputStream(file))
         buf.write(s.toByteArray())
@@ -30,4 +66,8 @@ class FileUtilsTest {
         buf.close()
         return String(bytes)
     }
+
+    private fun toInputStream(str: String) : InputStream {
+        return ByteArrayInputStream(str.toByteArray(Charsets.UTF_8))
+    }
 }