Fix and add unit tests

packages/block-editor/src/store/test/selectors.js

@@ -2694,6 +2694,7 @@ describe( 'selectors', () => {
 					byClientId: new Map(),
 					attributes: new Map(),
 					parents: new Map(),
+					order: new Map(),
 				},
 				blockListSettings: {},
 				settings: {
@@ -2711,6 +2712,7 @@ describe( 'selectors', () => {
 				blocks: {
 					byClientId: new Map(),
 					attributes: new Map(),
+					order: new Map(),
 				},
 				blockListSettings: {},
 				settings: {
@@ -2728,6 +2730,7 @@ describe( 'selectors', () => {
 					byClientId: new Map(),
 					attributes: new Map(),
 					parents: new Map(),
+					order: new Map(),
 				},
 				blockListSettings: {},
 				settings: {},
@@ -3002,7 +3005,7 @@ describe( 'selectors', () => {
 					byClientId: new Map(
 						Object.entries( {
 							block1: { name: 'core/test-block-ancestor' },
-							block2: { name: 'core/block' },
+							block2: { name: 'core/block1' },
 						} )
 					),
 					attributes: new Map(
@@ -3037,6 +3040,37 @@ describe( 'selectors', () => {
 			).toBe( true );
 		} );
 
+		it( 'should prevent blocks from being inserted within sections', () => {
+			const state = {
+				blocks: {
+					byClientId: new Map(
+						Object.entries( {
+							block1: { name: 'core/block' }, // reusable blocks are always sections.
+						} )
+					),
+					attributes: new Map(
+						Object.entries( {
+							block1: {},
+						} )
+					),
+					parents: new Map(
+						Object.entries( {
+							block1: '',
+						} )
+					),
+					order: new Map( [ [ '', [ 'block1' ] ] ] ),
+				},
+				blockListSettings: {
+					block1: {},
+				},
+				settings: {},
+				blockEditingModes: new Map(),
+			};
+			expect(
+				canInsertBlockType( state, 'core/test-block-a', 'block1' )
+			).toBe( false );
+		} );
+
 		it( 'should allow blocks to be inserted if both parent and ancestor restrictions are met', () => {
 			const state = {
 				blocks: {