add tests

tests/relativePositions.tests.js

@@ -0,0 +1,29 @@
+
+import * as Y from '../src/internals'
+import * as t from 'lib0/testing.js'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePosition = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, '1')
+  ytext.insert(0, 'abc')
+  ytext.insert(0, 'z')
+  ytext.insert(0, 'y')
+  ytext.insert(0, 'x')
+
+  // test if all positions are encoded and restored correctly
+  for (let i = 0; i < ytext.length; i++) {
+    // for all types of associations..
+    for (let assoc = -1; assoc < 2; assoc++) {
+      const rpos = Y.createRelativePositionFromTypeIndex(ytext, i, assoc)
+      const encodedRpos = Y.encodeRelativePosition(rpos)
+      const decodedRpos = Y.decodeRelativePosition(encodedRpos)
+      const absPos = /** @type {Y.AbsolutePosition} */ (Y.createAbsolutePositionFromRelativePosition(decodedRpos, ydoc))
+      t.assert(absPos.index === i)
+      t.assert(absPos.assoc === assoc)
+    }
+  }
+}