increase test coverage

extend test coverage

tests/unit/clear.test.js

@@ -0,0 +1,49 @@
+import { describe, expect, it } from 'vitest'
+import { clearSvgContentElementInit, init as initClear } from '../../packages/svgcanvas/core/clear.js'
+
+const buildCanvas = (showOutside = false) => {
+  const svgContent = document.createElementNS('http://www.w3.org/2000/svg', 'svg')
+  svgContent.append(document.createElementNS('http://www.w3.org/2000/svg', 'g'))
+  const svgRoot = document.createElementNS('http://www.w3.org/2000/svg', 'svg')
+  const curConfig = { dimensions: [300, 150], show_outside_canvas: showOutside }
+
+  return {
+    svgContent,
+    svgRoot,
+    curConfig,
+    canvas: {
+      getCurConfig: () => curConfig,
+      getSvgContent: () => svgContent,
+      getSvgRoot: () => svgRoot,
+      getDOMDocument: () => document
+    }
+  }
+}
+
+describe('clearSvgContentElementInit', () => {
+  it('clears existing children and sets canvas attributes', () => {
+    const { canvas, svgContent, svgRoot } = buildCanvas(false)
+    initClear(canvas)
+
+    clearSvgContentElementInit()
+
+    expect(svgRoot.contains(svgContent)).toBe(true)
+    expect(svgContent.childNodes[0].nodeType).toBe(Node.COMMENT_NODE)
+    expect(svgContent.getAttribute('id')).toBe('svgcontent')
+    expect(svgContent.getAttribute('width')).toBe('300')
+    expect(svgContent.getAttribute('height')).toBe('150')
+    expect(svgContent.getAttribute('x')).toBe('300')
+    expect(svgContent.getAttribute('y')).toBe('150')
+    expect(svgContent.getAttribute('overflow')).toBe('hidden')
+    expect(svgContent.getAttribute('xmlns')).toBe('http://www.w3.org/2000/svg')
+  })
+
+  it('honors show_outside_canvas by leaving overflow visible', () => {
+    const { canvas, svgContent } = buildCanvas(true)
+    initClear(canvas)
+
+    clearSvgContentElementInit()
+
+    expect(svgContent.getAttribute('overflow')).toBe('visible')
+  })
+})