Improve string resize flow

imgui-binding/src/test/java/imgui/ImStringTest.java

@@ -0,0 +1,55 @@
+package imgui;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ImStringTest {
+    @Test
+    public void testCreation() {
+        ImString str = new ImString(10);
+        assertEquals("", str.get());
+        assertEquals(0, str.getLength(), "String length should be 0, since no data was provided");
+        assertEquals(10 + 1, str.getBufferSize(), "Buffer size must be 'length + 1', +1 - size of the ImGui caret");
+
+        str = new ImString("test");
+        assertEquals("test", str.get());
+        assertEquals(4, str.getLength());
+        assertEquals(4 + 1, str.getBufferSize());
+
+        str = new ImString("test", 10);
+        assertEquals("test", str.get());
+        assertEquals(4, str.getLength());
+        assertEquals(10 + 1, str.getBufferSize());
+    }
+
+    @Test
+    public void testGet() {
+        final ImString str = new ImString("test");
+        assertEquals("test", str.get());
+        assertEquals(str.get(), str.toString(), "ImString#toString() must return value which should be equal to ImString#get()");
+    }
+
+    @Test
+    public void testSet() {
+        final ImString str = new ImString(3);
+        assertEquals("", str.get());
+        assertEquals(0, str.getLength());
+        assertEquals(3 + 1, str.getBufferSize());
+
+        str.set("test");
+        assertEquals("tes", str.get());
+        assertEquals(3, str.getLength());
+        assertEquals(3 + 1, str.getBufferSize());
+
+        str.set("test", true, 0);
+        assertEquals("test", str.get());
+        assertEquals(4, str.getLength());
+        assertEquals(4 + 1, str.getBufferSize());
+
+        str.set("0123456789", true);
+        assertEquals("0123456789", str.get());
+        assertEquals(10, str.getLength());
+        assertEquals(10 + str.resizeFactor + 1, str.getBufferSize());
+    }
+}