Add file tests

src/test/kotlin/org/hmcore/extensions/FileTest.kt

@@ -0,0 +1,73 @@
+package org.hmcore.extensions
+
+import io.mockk.*
+import java.io.File
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class FileTest {
+    @Test
+    fun `Ensure exists should create a file with default content if it does not exist`() {
+        val file = mockk<File>()
+        mockkStatic("kotlin.io.FilesKt__FileReadWriteKt")
+
+        every { file.exists() } returns false
+        every { file.createNewFile() } returns true
+        every { file.writeText(any()) } just Runs
+
+        file.ensureExists("Default Text")
+
+        verifySequence {
+            file.exists()
+            file.createNewFile()
+            file.writeText("Default Text")
+        }
+    }
+
+    @Test
+    fun `Ensure exists should create a file if supplied with null but not write text`() {
+        val file = mockk<File>()
+        mockkStatic("kotlin.io.FilesKt__FileReadWriteKt")
+
+        every { file.exists() } returns false
+        every { file.createNewFile() } returns true
+        every { file.writeText(any()) } just Runs
+
+        file.ensureExists(null)
+
+        verifySequence {
+            file.exists()
+            file.createNewFile()
+        }
+    }
+
+    @Test
+    fun `Ensure exists should not touch the file if it exists`() {
+        val file = mockk<File>()
+        mockkStatic("kotlin.io.FilesKt__FileReadWriteKt")
+
+        every { file.exists() } returns true
+        every { file.createNewFile() } returns true
+        every { file.writeText(any()) } just Runs
+
+        file.ensureExists(null)
+
+        verifySequence {
+            file.exists()
+        }
+    }
+
+    @Test
+    fun `Ensure exists should return itself`() {
+        val file = mockk<File>()
+        mockkStatic("kotlin.io.FilesKt__FileReadWriteKt")
+
+        every { file.exists() } returns true
+        every { file.createNewFile() } returns true
+        every { file.writeText(any()) } just Runs
+
+        val f2 = file.ensureExists(null)
+
+        assertEquals(file, f2)
+    }
+}