improve tests

src/main/kotlin/ley/anvil/modpacktools/util/CLIUtil.kt

@@ -19,9 +19,8 @@ fun fPrint(x: Any?, vararg formatters: (String) -> String) = System.out.fPrint(x
  * @param x the object to print
  * @param formatters the formatters to apply to x, they will be ran in the order they are supplied in
  */
-fun PrintStream.fPrint(x: Any?, vararg formatters: (String) -> String) = this.print(
-    formatters.fold(x.toString()) {acc, f -> f(acc)}
-)
+fun PrintStream.fPrint(x: Any?, vararg formatters: (String) -> String) =
+    this.print(formatters.fold(x.toString()) {acc, f -> f(acc)})
 
 /**
  * applies all given formatters to the string representation of the object and then prints it with a newline at the end

src/test/kotlin/ley/anvil/modpacktools/util/CLIUtilTest.kt

@@ -6,13 +6,24 @@ import java.io.ByteArrayOutputStream
 import java.io.PrintStream
 
 class CLIUtilTest {
+    fun prntStr(f: PrintStream.() -> Unit): String =
+        ByteArrayOutputStream().apply {
+            PrintStream(this, true, "UTF-8").use(f)
+        }.use {it.toString("UTF-8")}
+
     @Test
     fun testFPrintln() {
-        val baos = ByteArrayOutputStream()
-        PrintStream(baos, true, "UTF-8").use {
-            it.fPrintln("Test String", {s -> "$s Formatted"})
-        }
+        assertEquals(
+            "Test String Formatted\n",
+            prntStr {this.fPrintln("Test String", {"$it Formatted"})}
+        )
+    }
 
-        assertEquals("Test String Formatted\n", baos.toString("UTF-8"))
+    @Test
+    fun testFPrintlnNull() {
+        assertEquals(
+            "null\n",
+            prntStr {this.fPrintln(null)}
+        )
     }
 }