Add MutableProvider#set(lazyValue)

Author: NichtStudioCode

src/main/kotlin/xyz/xenondevs/commons/provider/MutableProvider.kt

@@ -90,6 +90,13 @@ interface MutableProvider<T> : Provider<T> {
         update(DeferredValue.Direct(value))
     }
 
+    /**
+     * Sets the value of [this][MutableProvider] to the result of [lazyValue].
+     */
+    fun set(lazyValue: () -> T) {
+        update(DeferredValue.Lazy(lazyValue))
+    }
+    
     /**
      * Sets the value of [this][MutableProvider] to [value].
      */

src/test/kotlin/xyz/xenondevs/commons/provider/CoreProviderTest.kt

@@ -114,6 +114,23 @@ class CoreProviderTest {
         assertEquals(0, leafBUntransform)
     }
 
+    @Test
+    fun testProviderSetLazyIsLazy() {
+        var i = 0
+        
+        val provider = mutableProvider { ++i }
+        assertEquals(0, i)
+        assertEquals(1, provider.get())
+        assertEquals(1, provider.get())
+        assertEquals(1, i)
+        
+        provider.set { ++i }
+        assertEquals(1, i)
+        assertEquals(2, provider.get())
+        assertEquals(2, provider.get())
+        assertEquals(2, i)
+    }
+    
     @Test
     fun testProviderSubscriber() {
         var invoked = false