diff --git a/markwon-core/src/test/java/ru/noties/markwon/MarkwonSpansFactoryTest.java b/markwon-core/src/test/java/ru/noties/markwon/MarkwonSpansFactoryTest.java
new file mode 100644
index 00000000..a2cb36ff
--- /dev/null
+++ b/markwon-core/src/test/java/ru/noties/markwon/MarkwonSpansFactoryTest.java
@@ -0,0 +1,68 @@
+package ru.noties.markwon;
+
+import org.commonmark.node.BlockQuote;
+import org.commonmark.node.Image;
+import org.commonmark.node.Link;
+import org.commonmark.node.ListItem;
+import org.commonmark.node.Text;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.mock;
+
+public class MarkwonSpansFactoryTest {
+
+    private MarkwonSpansFactoryImpl.BuilderImpl builder;
+
+    @Before
+    public void before() {
+        builder = new MarkwonSpansFactoryImpl.BuilderImpl();
+    }
+
+    @Test
+    public void builder_set() {
+        final SpanFactory factory = mock(SpanFactory.class);
+        builder.setFactory(Text.class, factory);
+        builder.setFactory(Text.class, factory);
+        assertEquals(factory, builder.build().get(Text.class));
+        assertEquals(factory, builder.build().require(Text.class));
+    }
+
+    @Test
+    public void builder_get_absent() {
+        // nothing is present
+        assertNull(builder.getFactory(Image.class));
+    }
+
+    @Test
+    public void builder_get_present() {
+        final SpanFactory factory = mock(SpanFactory.class);
+        builder.setFactory(ListItem.class, factory);
+        assertEquals(factory, builder.getFactory(ListItem.class));
+        assertEquals(factory, builder.requireFactory(ListItem.class));
+    }
+
+    @Test
+    public void builder_require_fail() {
+        try {
+            builder.requireFactory(Link.class);
+            fail();
+        } catch (NullPointerException e) {
+            assertTrue(e.getMessage(), e.getMessage().contains(Link.class.getName()));
+        }
+    }
+
+    @Test
+    public void instance_require_fail() {
+        try {
+            builder.build().require(BlockQuote.class);
+            fail();
+        } catch (NullPointerException e) {
+            assertTrue(e.getMessage(), e.getMessage().contains(BlockQuote.class.getName()));
+        }
+    }
+}
\ No newline at end of file
diff --git a/markwon-core/src/test/java/ru/noties/markwon/core/CorePluginTest.java b/markwon-core/src/test/java/ru/noties/markwon/core/CorePluginTest.java
index 1cbf908b..f3edf945 100644
--- a/markwon-core/src/test/java/ru/noties/markwon/core/CorePluginTest.java
+++ b/markwon-core/src/test/java/ru/noties/markwon/core/CorePluginTest.java
@@ -162,6 +162,12 @@ public class CorePluginTest {
                 throw new RuntimeException();
             }
 
+            @NonNull
+            @Override
+            public <N extends Node> SpanFactory requireFactory(@NonNull Class<N> node) {
+                throw new RuntimeException();
+            }
+
             @NonNull
             @Override
             public MarkwonSpansFactory build() {