add MockedD3.ts

packages/mermaid/src/tests/MockedD3.ts

@@ -0,0 +1,119 @@
+/**
+ * This is a mocked/stubbed version of the d3 Selection type. Each of the main functions are all
+ * mocked (via vi.fn()) so you can track if they have been called, etc.
+ */
+export class MockedD3 {
+  public attribs = new Map<string, string | null>();
+  public id: string | undefined = '';
+  _children: MockedD3[] = [];
+
+  constructor(givenId = 'mock-id') {
+    this.id = givenId;
+  }
+
+  /** Helpful utility during development/debugging. This is not a real d3 function */
+  public listChildren(): string {
+    return this._children
+      .map((child) => {
+        return child.id;
+      })
+      .join(', ');
+  }
+
+  select = vi.fn().mockImplementation(({ select_str = '' }): MockedD3 => {
+    // Get the id from an argument string. if it is of the form [id='some-id'], strip off the
+    // surrounding id[..]
+    const stripSurroundRegexp = /\[id='(.*)'\]/;
+    const matchedSurrounds = select_str.match(stripSurroundRegexp);
+    const cleanId = matchedSurrounds ? matchedSurrounds[1] : select_str;
+    return new MockedD3(cleanId);
+  });
+
+  append = vi
+    .fn()
+    .mockImplementation(function (this: MockedD3, type: string, id = '' + '-appended'): MockedD3 {
+      const newMock = new MockedD3(id);
+      newMock.attribs.set('type', type);
+      this._children.push(newMock);
+      return newMock;
+    });
+
+  // NOTE: The d3 implementation allows for a selector ('beforeSelector' arg below).
+  //   With this mocked implementation, we assume it will always refer to an node id
+  //   and will always be of the form "#[id of the node to insert before]".
+  //   To keep this simple, any leading '#' is removed and the resulting string is the node id searched.
+  insert = (type: string, beforeSelector?: string, id = this.id + '-inserted'): MockedD3 => {
+    const newMock = new MockedD3(id);
+    newMock.attribs.set('type', type);
+    if (beforeSelector === undefined) {
+      this._children.push(newMock);
+    } else {
+      const idOnly = beforeSelector[0] == '#' ? beforeSelector.substring(1) : beforeSelector;
+      const foundIndex = this._children.findIndex((child) => child.id === idOnly);
+      if (foundIndex < 0) this._children.push(newMock);
+      else this._children.splice(foundIndex, 0, newMock);
+    }
+    return newMock;
+  };
+
+  attr(attrName: string): null | undefined | string | number;
+  // attr(attrName: string, attrValue: string): MockedD3;
+  attr(attrName: string, attrValue?: string): null | undefined | string | number | MockedD3 {
+    if (arguments.length === 1) {
+      return this.attribs.get(attrName);
+    } else {
+      if (attrName === 'id') this.id = attrValue; // also set the id explicitly
+      if (attrValue !== undefined) this.attribs.set(attrName, attrValue);
+      return this;
+    }
+  }
+
+  public lower(attrValue = '') {
+    this.attribs.set('lower', attrValue);
+    return this;
+  }
+  public style(attrValue = '') {
+    this.attribs.set('style', attrValue);
+    return this;
+  }
+  public text(attrValue = '') {
+    this.attribs.set('text', attrValue);
+    return this;
+  }
+  // NOTE: Arbitrarily returns an empty object. The return value could be something different with a mockReturnValue() or mockImplementation()
+  public node = vi.fn().mockReturnValue({});
+
+  nodes = vi.fn().mockImplementation(function (this: MockedD3): MockedD3[] {
+    return this._children;
+  });
+
+  // This will try to use attrs that have been set.
+  getBBox = () => {
+    const x = this.attribs.has('x') ? this.attribs.get('x') : 20;
+    const y = this.attribs.has('y') ? this.attribs.get('y') : 30;
+    const width = this.attribs.has('width') ? this.attribs.get('width') : 140;
+    const height = this.attribs.has('height') ? this.attribs.get('height') : 250;
+    return {
+      x: x,
+      y: y,
+      width: width,
+      height: height,
+    };
+  };
+
+  // --------------------------------------------------------------------------------
+  // The following functions are here for completeness.  They simply return a vi.fn()
+
+  insertBefore = vi.fn();
+  curveBasis = vi.fn();
+  curveBasisClosed = vi.fn();
+  curveBasisOpen = vi.fn();
+  curveLinear = vi.fn();
+  curveLinearClosed = vi.fn();
+  curveMonotoneX = vi.fn();
+  curveMonotoneY = vi.fn();
+  curveNatural = vi.fn();
+  curveStep = vi.fn();
+  curveStepAfter = vi.fn();
+  curveStepBefore = vi.fn();
+}