diff --git a/packages/mermaid/src/diagrams/git/gitGraph.parser.spec.ts b/packages/mermaid/src/diagrams/git/gitGraph.parser.spec.ts
deleted file mode 100644
index 1a38a8217..000000000
--- a/packages/mermaid/src/diagrams/git/gitGraph.parser.spec.ts
+++ /dev/null
@@ -1,74 +0,0 @@
-import { describe, it, expect, beforeEach, vi } from 'vitest';
-import { parser } from './gitGraphParser.js';
-import { db } from './gitGraphAst.js';
-
-const parseInput = async (input: string) => {
-  await parser.parse(input);
-};
-
-const spyOn = vi.spyOn;
-
-describe('GitGraph Parsing', function () {
-  beforeEach(() => {
-    db.clear();
-  });
-  it('should parse a default commit statement', async () => {
-    const input = `gitGraph:
-    commit
-    `;
-    const commitSpy = spyOn(db, 'commit');
-    await parseInput(input);
-
-    expect(commitSpy).toHaveBeenCalledWith('', undefined, 0, []);
-    commitSpy.mockRestore();
-  });
-
-  it('should parse a basic branch statement with just a name', async () => {
-    const input = `gitGraph:
-    branch newBranch
-    `;
-    const branchSpy = spyOn(db, 'branch');
-    await parseInput(input);
-    expect(branchSpy).toHaveBeenCalledWith('newBranch', 0);
-    branchSpy.mockRestore();
-  });
-
-  it('should parse a basic checkout statement', async () => {
-    const input = `gitGraph:
-    branch newBranch
-    checkout newBranch
-    `;
-    const checkoutSpy = spyOn(db, 'checkout');
-    await parseInput(input);
-    expect(checkoutSpy).toHaveBeenCalledWith('newBranch');
-    checkoutSpy.mockRestore();
-  });
-
-  it('should parse a basic merge statement', async () => {
-    const input = `gitGraph:
-    commit
-    branch newBranch
-    checkout newBranch
-    commit
-    checkout main
-    merge newBranch`;
-    const mergeSpy = spyOn(db, 'merge');
-    await parseInput(input);
-    expect(mergeSpy).toHaveBeenCalledWith('newBranch', '', undefined, []);
-    mergeSpy.mockRestore();
-  });
-
-  it('should parse cherry-picking', async () => {
-    const input = `gitGraph
-    commit id: "ZERO"
-    branch develop
-    commit id:"A"
-    checkout main
-    cherry-pick id:"A"
-    `;
-    const cherryPickSpy = spyOn(db, 'cherryPick');
-    await parseInput(input);
-    expect(cherryPickSpy).toHaveBeenCalledWith('A', '', undefined, undefined);
-    cherryPickSpy.mockRestore();
-  });
-});
diff --git a/packages/mermaid/src/diagrams/git/gitGraphParser.ts b/packages/mermaid/src/diagrams/git/gitGraphParser.ts
index b014d7e57..1ca863329 100644
--- a/packages/mermaid/src/diagrams/git/gitGraphParser.ts
+++ b/packages/mermaid/src/diagrams/git/gitGraphParser.ts
@@ -11,9 +11,10 @@ import type {
   MergeAst,
   CommitAst,
   BranchAst,
+  GitGraphDBProvider,
 } from './gitGraphTypes.js';
 
-const populate = (ast: GitGraph) => {
+const populate = (ast: GitGraph, db: GitGraphDBProvider) => {
   populateCommonDb(ast, db);
   // @ts-ignore: this wont exist if the direction is not specified
   if (ast.dir) {
@@ -21,71 +22,107 @@ const populate = (ast: GitGraph) => {
     db.setDirection(ast.dir);
   }
   for (const statement of ast.statements) {
-    parseStatement(statement);
+    parseStatement(statement, db);
   }
 };
 
-const parseStatement = (statement: any) => {
-  switch (statement.$type) {
-    case 'Commit':
-      parseCommit(statement);
-      break;
-    case 'Branch':
-      parseBranch(statement);
-      break;
-    case 'Merge':
-      parseMerge(statement);
-      break;
-    case 'Checkout':
-      parseCheckout(statement);
-      break;
-    case 'CherryPicking':
-      parseCherryPicking(statement);
-      break;
-    default:
-      log.error(`Unknown statement type`);
+const parseStatement = (statement: any, db: GitGraphDBProvider) => {
+  const parsers: Record<string, (stmt: any) => void> = {
+    Commit: (stmt) => db.commit(...parseCommit(stmt)),
+    Branch: (stmt) => db.branch(...parseBranch(stmt)),
+    Merge: (stmt) => db.merge(...parseMerge(stmt)),
+    Checkout: (stmt) => db.checkout(parseCheckout(stmt)),
+    CherryPicking: (stmt) => db.cherryPick(...parseCherryPicking(stmt)),
+  };
+
+  const parser = parsers[statement.$type];
+  if (parser) {
+    parser(statement);
+  } else {
+    log.error(`Unknown statement type: ${statement.$type}`);
   }
 };
 
-const parseCommit = (commit: CommitAst) => {
+const parseCommit = (commit: CommitAst): [string, string, number, string[] | undefined] => {
   const id = commit.id;
   const message = commit.message ?? '';
   const type = commit.type !== undefined ? commitType[commit.type] : commitType.NORMAL;
   const tags = commit.tags ?? undefined;
 
-  db.commit(message, id, type, tags);
+  return [message, id, type, tags];
 };
 
-const parseBranch = (branch: BranchAst) => {
+const parseBranch = (branch: BranchAst): [string, number] => {
   const name = branch.name;
   const order = branch.order ?? 0;
-  db.branch(name, order);
+  return [name, order];
 };
 
-const parseMerge = (merge: MergeAst) => {
+const parseMerge = (
+  merge: MergeAst
+): [string, string, number | undefined, string[] | undefined] => {
   const branch = merge.branch;
   const id = merge.id ?? '';
   const type = merge.type !== undefined ? commitType[merge.type] : undefined;
   const tags = merge.tags ?? undefined;
-  db.merge(branch, id, type, tags);
+  return [branch, id, type, tags];
 };
 
-const parseCheckout = (checkout: CheckoutAst) => {
+const parseCheckout = (checkout: CheckoutAst): string => {
   const branch = checkout.branch;
-  db.checkout(branch);
+  return branch;
 };
 
-const parseCherryPicking = (cherryPicking: CherryPickingAst) => {
+const parseCherryPicking = (
+  cherryPicking: CherryPickingAst
+): [string, string, string[] | undefined, string] => {
   const id = cherryPicking.id;
   const tags = cherryPicking.tags?.length === 0 ? undefined : cherryPicking.tags;
   const parent = cherryPicking.parent;
-  db.cherryPick(id, '', tags, parent);
+  return [id, '', tags, parent];
 };
 
 export const parser: ParserDefinition = {
   parse: async (input: string): Promise<void> => {
     const ast: GitGraph = await parse('gitGraph', input);
     log.debug(ast);
-    populate(ast);
+    populate(ast, db);
   },
 };
+
+if (import.meta.vitest) {
+  const { it, expect, describe } = import.meta.vitest;
+
+  const mockDB: GitGraphDBProvider = {
+    commitType: commitType,
+    setDirection: vi.fn(),
+    commit: vi.fn(),
+    branch: vi.fn(),
+    merge: vi.fn(),
+    cherryPick: vi.fn(),
+    checkout: vi.fn(),
+  };
+
+  describe('GitGraph Parser', () => {
+    it('should parse a commit statement', () => {
+      const commit = {
+        $type: 'Commit',
+        id: '1',
+        message: 'test',
+        tags: ['tag1', 'tag2'],
+        type: 'NORMAL',
+      };
+      parseStatement(commit, mockDB);
+      expect(mockDB.commit).toHaveBeenCalledWith('test', '1', 0, ['tag1', 'tag2']);
+    });
+    it('should parse a branch statement', () => {
+      const branch = {
+        $type: 'Branch',
+        name: 'newBranch',
+        order: 1,
+      };
+      parseStatement(branch, mockDB);
+      expect(mockDB.branch).toHaveBeenCalledWith('newBranch', 1);
+    });
+  });
+}
diff --git a/packages/mermaid/src/diagrams/git/gitGraphRenderer.ts b/packages/mermaid/src/diagrams/git/gitGraphRenderer.ts
index 0408baa23..c3862e581 100644
--- a/packages/mermaid/src/diagrams/git/gitGraphRenderer.ts
+++ b/packages/mermaid/src/diagrams/git/gitGraphRenderer.ts
@@ -4,7 +4,12 @@ import { log } from '../../logger.js';
 import utils from '../../utils.js';
 import type { DrawDefinition } from '../../diagram-api/types.js';
 import type d3 from 'd3';
-import type { CommitType, Commit, GitGraphDB, DiagramOrientation } from './gitGraphTypes.js';
+import type {
+  CommitType,
+  Commit,
+  GitGraphDBRenderProvider,
+  DiagramOrientation,
+} from './gitGraphTypes.js';
 import type { GitGraphDiagramConfig } from '../../config.type.js';
 
 let allCommitsDict = new Map();
@@ -770,7 +775,9 @@ const drawArrow = (
       }
     }
   }
-
+  if (lineDef === undefined) {
+    throw new Error('Line definition not found');
+  }
   svg
     .append('path')
     .attr('d', lineDef)
@@ -889,7 +896,7 @@ export const draw: DrawDefinition = function (txt, id, ver, diagObj) {
     throw new Error('GitGraph config not found');
   }
   const rotateCommitLabel = gitGraphConfig.rotateCommitLabel ?? false;
-  const db = diagObj.db as GitGraphDB;
+  const db = diagObj.db as GitGraphDBRenderProvider;
   allCommitsDict = db.getCommits();
   const branches = db.getBranchesAsObjArray();
   dir = db.getDirection();
diff --git a/packages/mermaid/src/diagrams/git/gitGraphTypes.ts b/packages/mermaid/src/diagrams/git/gitGraphTypes.ts
index b473dd874..b888cc297 100644
--- a/packages/mermaid/src/diagrams/git/gitGraphTypes.ts
+++ b/packages/mermaid/src/diagrams/git/gitGraphTypes.ts
@@ -1,5 +1,5 @@
-import type { DiagramDB } from '../../diagram-api/types.js';
 import type { GitGraphDiagramConfig } from '../../config.type.js';
+import type { DiagramDBBase } from '../../diagram-api/types.js';
 
 export interface CommitType {
   NORMAL: number;
@@ -66,27 +66,13 @@ export interface CherryPickingAst {
   parent: string;
 }
 
-export interface GitGraphDB extends DiagramDB {
-  // config
-  getConfig: () => GitGraphDiagramConfig | undefined;
-
-  // common db
-  clear: () => void;
-  setDiagramTitle: (title: string) => void;
-  getDiagramTitle: () => string;
-  setAccTitle: (title: string) => void;
-  getAccTitle: () => string;
-  setAccDescription: (description: string) => void;
-  getAccDescription: () => string;
-
-  // diagram db
+export interface GitGraphDB extends DiagramDBBase<GitGraphDiagramConfig> {
   commitType: CommitType;
-  setDirection: (direction: DiagramOrientation) => void;
-  getDirection: () => DiagramOrientation;
-  setOptions: (options: string) => void;
-  getOptions: () => string;
-  commit: (msg: string, id: string, type: number, tags?: string[] | undefined) => void;
-  branch: (name: string, order: number) => void;
+  setDirection: (dir: DiagramOrientation) => void;
+  setOptions: (rawOptString: string) => void;
+  getOptions: () => any;
+  commit: (msg: string, id: string, type: number, tags?: string[]) => void;
+  branch: (name: string, order?: number) => void;
   merge: (
     otherBranch: string,
     customId?: string,
@@ -101,12 +87,47 @@ export interface GitGraphDB extends DiagramDB {
   ) => void;
   checkout: (branch: string) => void;
   prettyPrint: () => void;
+  clear: () => void;
   getBranchesAsObjArray: () => { name: string }[];
   getBranches: () => Map<string, string | null>;
   getCommits: () => Map<string, Commit>;
   getCommitsArray: () => Commit[];
   getCurrentBranch: () => string;
+  getDirection: () => DiagramOrientation;
   getHead: () => Commit | null;
 }
 
+export interface GitGraphDBParseProvider extends Partial<GitGraphDB> {
+  commitType: CommitType;
+  setDirection: (dir: DiagramOrientation) => void;
+  commit: (msg: string, id: string, type: number, tags?: string[]) => void;
+  branch: (name: string, order?: number) => void;
+  merge: (
+    otherBranch: string,
+    customId?: string,
+    overrideType?: number,
+    customTags?: string[]
+  ) => void;
+  cherryPick: (
+    sourceId: string,
+    targetId: string,
+    tags: string[] | undefined,
+    parentCommitId: string
+  ) => void;
+  checkout: (branch: string) => void;
+}
+
+export interface GitGraphDBRenderProvider extends Partial<GitGraphDB> {
+  prettyPrint: () => void;
+  clear: () => void;
+  getBranchesAsObjArray: () => { name: string }[];
+  getBranches: () => Map<string, string | null>;
+  getCommits: () => Map<string, Commit>;
+  getCommitsArray: () => Commit[];
+  getCurrentBranch: () => string;
+  getDirection: () => DiagramOrientation;
+  getHead: () => Commit | null;
+  getDiagramTitle: () => string;
+}
+
 export type DiagramOrientation = 'LR' | 'TB' | 'BT';