[ENG-12319] Registration schema responses empty in API (#1065)

- Ticket: https://openscience.atlassian.net/browse/ENG-12319
- Feature flag: n/a

## Summary of Changes
1. Fixed issue with no `page-heading`.
2. Added unit tests for mapper.

Author: nsemets

src/app/shared/mappers/registration/page-schema.mapper.spec.ts

@@ -0,0 +1,156 @@
+import { BlockType } from '@osf/shared/enums/block-type.enum';
+import { FieldType } from '@osf/shared/enums/field-type.enum';
+import { SchemaBlocksResponseJsonApi } from '@osf/shared/models/registration/schema-blocks-json-api.model';
+
+import { PageSchemaMapper } from './page-schema.mapper';
+
+type SchemaBlock = SchemaBlocksResponseJsonApi['data'][number];
+
+function block(id: string, blockType: BlockType, overrides: Partial<SchemaBlock['attributes']> = {}): SchemaBlock {
+  return {
+    id,
+    type: 'schema-blocks',
+    attributes: {
+      block_type: blockType,
+      display_text: '',
+      example_text: '',
+      help_text: '',
+      index: 0,
+      registration_response_key: null,
+      required: false,
+      schema_block_group_key: id,
+      ...overrides,
+    },
+  };
+}
+
+function response(blocks: SchemaBlock[]): SchemaBlocksResponseJsonApi {
+  return { data: blocks, meta: { total: blocks.length } };
+}
+
+describe('PageSchemaMapper', () => {
+  it('should return no pages when the response has no blocks', () => {
+    expect(PageSchemaMapper.fromSchemaBlocksResponse(response([]))).toEqual([]);
+  });
+
+  it('should map a page heading and attach its question', () => {
+    const pages = PageSchemaMapper.fromSchemaBlocksResponse(
+      response([
+        block('page-1', BlockType.PageHeading, { display_text: 'Study &amp; design', help_text: 'Help' }),
+        block('q-1', BlockType.QuestionLabel, {
+          display_text: 'Research questions',
+          schema_block_group_key: 'g1',
+        }),
+        block('input-1', BlockType.LongTextInput, {
+          registration_response_key: 'q1',
+          required: true,
+          schema_block_group_key: 'g1',
+        }),
+      ])
+    );
+
+    expect(pages).toEqual([
+      {
+        id: 'page-1',
+        title: 'Study & design',
+        helpText: 'Help',
+        questions: [
+          {
+            id: 'q-1',
+            displayText: 'Research questions',
+            helpText: '',
+            exampleText: '',
+            required: true,
+            groupKey: 'g1',
+            responseKey: 'q1',
+            fieldType: FieldType.TextArea,
+          },
+        ],
+      },
+    ]);
+  });
+
+  it('should attach section questions to the section', () => {
+    const pages = PageSchemaMapper.fromSchemaBlocksResponse(
+      response([
+        block('page-1', BlockType.PageHeading, { display_text: 'Methods' }),
+        block('section-1', BlockType.SectionHeading, { display_text: 'Analysis' }),
+        block('q-1', BlockType.QuestionLabel, { display_text: 'Data processing', schema_block_group_key: 'g1' }),
+        block('input-1', BlockType.ShortTextInput, {
+          registration_response_key: 'q2',
+          required: true,
+          schema_block_group_key: 'g1',
+        }),
+      ])
+    );
+
+    expect(pages[0].questions).toEqual([]);
+    expect(pages[0].sections).toEqual([
+      {
+        id: 'section-1',
+        title: 'Analysis',
+        helpText: '',
+        questions: [
+          {
+            id: 'q-1',
+            displayText: 'Data processing',
+            helpText: '',
+            exampleText: '',
+            required: true,
+            groupKey: 'g1',
+            responseKey: 'q2',
+            fieldType: FieldType.Text,
+          },
+        ],
+      },
+    ]);
+  });
+
+  it('should wrap questions without a page heading into one page', () => {
+    const pages = PageSchemaMapper.fromSchemaBlocksResponse(
+      response([
+        block('q-1', BlockType.QuestionLabel, { display_text: 'Research questions', schema_block_group_key: 'g1' }),
+        block('input-1', BlockType.LongTextInput, {
+          registration_response_key: 'q1',
+          required: true,
+          schema_block_group_key: 'g1',
+        }),
+        block('q-2', BlockType.QuestionLabel, { display_text: 'Upload files', schema_block_group_key: 'g2' }),
+        block('input-2', BlockType.FileInput, {
+          registration_response_key: '53-7',
+          required: false,
+          schema_block_group_key: 'g2',
+        }),
+      ])
+    );
+
+    expect(pages).toEqual([
+      {
+        id: 'q-1',
+        title: '',
+        questions: [
+          {
+            id: 'q-1',
+            displayText: 'Research questions',
+            helpText: '',
+            exampleText: '',
+            required: true,
+            groupKey: 'g1',
+            responseKey: 'q1',
+            fieldType: FieldType.TextArea,
+          },
+          {
+            id: 'q-2',
+            displayText: 'Upload files',
+            helpText: '',
+            exampleText: '',
+            required: false,
+            groupKey: 'g2',
+            responseKey: '53-7',
+            fieldType: FieldType.File,
+          },
+        ],
+      },
+    ]);
+  });
+});

src/app/shared/mappers/registration/page-schema.mapper.ts

@@ -7,6 +7,7 @@ import { SchemaBlocksResponseJsonApi } from '@shared/models/registration/schema-
 export class PageSchemaMapper {
   static fromSchemaBlocksResponse(response: SchemaBlocksResponseJsonApi): PageSchema[] {
     const pages: PageSchema[] = [];
+    const unpagedQuestions: Question[] = [];
     let currentPage!: PageSchema;
     let currentQuestion: Question | null = null;
     let currentSection: Section | null = null;
@@ -75,6 +76,8 @@ export class PageSchemaMapper {
           } else if (currentPage) {
             currentPage.questions = currentPage.questions || [];
             currentPage.questions.push(currentQuestion);
+          } else {
+            unpagedQuestions.push(currentQuestion);
           }
           break;
 
@@ -94,6 +97,8 @@ export class PageSchemaMapper {
           } else if (currentPage) {
             currentPage.questions = currentPage.questions || [];
             currentPage.questions.push(currentQuestion);
+          } else {
+            unpagedQuestions.push(currentQuestion);
           }
           break;
 
@@ -151,6 +156,14 @@ export class PageSchemaMapper {
       }
     });
 
+    if (!pages.length && unpagedQuestions.length) {
+      pages.push({
+        id: unpagedQuestions[0].id,
+        title: '',
+        questions: unpagedQuestions,
+      });
+    }
+
     return pages;
   }
 }