test(svg-constants-type-compiler): verify TypeScript Compiler Validation & Schema Constraints Stability

Author: RavindiFernando

lib/svg/constants.type-compiler.test.ts

@@ -0,0 +1,48 @@
+import { describe, expectTypeOf, it } from 'vitest';
+import {
+  CONTRIBUTION_MILESTONES,
+  FONT_MAP,
+  GHOST_HEIGHT_PX,
+  LINEAR_SCALE_MULTIPLIER,
+  LOG_SCALE_MULTIPLIER,
+  MAX_LINEAR_HEIGHT,
+  MAX_LOG_HEIGHT,
+  SVG_HEIGHT,
+  SVG_WIDTH,
+} from './constants';
+
+describe('lib/svg/constants — TypeScript type compiler', () => {
+  it('numeric dimension constants are typed as number', () => {
+    expectTypeOf(SVG_WIDTH).toBeNumber();
+    expectTypeOf(SVG_HEIGHT).toBeNumber();
+    expectTypeOf(GHOST_HEIGHT_PX).toBeNumber();
+    expectTypeOf(MAX_LOG_HEIGHT).toBeNumber();
+    expectTypeOf(MAX_LINEAR_HEIGHT).toBeNumber();
+  });
+
+  it('scale multiplier constants are typed as number', () => {
+    expectTypeOf(LOG_SCALE_MULTIPLIER).toBeNumber();
+    expectTypeOf(LINEAR_SCALE_MULTIPLIER).toBeNumber();
+  });
+
+  it('FONT_MAP satisfies Record<string, string> — keys and values are both strings', () => {
+    expectTypeOf(FONT_MAP).toEqualTypeOf<Record<string, string>>();
+    expectTypeOf(FONT_MAP).not.toEqualTypeOf<Record<string, number>>();
+  });
+
+  it('CONTRIBUTION_MILESTONES satisfies a readonly number array and its elements are numbers', () => {
+    expectTypeOf(CONTRIBUTION_MILESTONES).toEqualTypeOf<number[]>();
+    expectTypeOf(CONTRIBUTION_MILESTONES).items.toBeNumber();
+  });
+
+  it('a function accepting number accepts all numeric constants without type errors', () => {
+    const requiresNumber = (n: number): number => n;
+
+    expectTypeOf(requiresNumber).parameter(0).toBeNumber();
+    // Verify each constant satisfies the number parameter type
+    expectTypeOf(SVG_WIDTH).toEqualTypeOf<Parameters<typeof requiresNumber>[0]>();
+    expectTypeOf(SVG_HEIGHT).toEqualTypeOf<Parameters<typeof requiresNumber>[0]>();
+    expectTypeOf(LOG_SCALE_MULTIPLIER).toEqualTypeOf<Parameters<typeof requiresNumber>[0]>();
+    expectTypeOf(LINEAR_SCALE_MULTIPLIER).toEqualTypeOf<Parameters<typeof requiresNumber>[0]>();
+  });
+});