test(breakpoint): add unit tests

tests/Breakpoint/Breakpoint.test.svelte

@@ -0,0 +1,28 @@
+<script lang="ts">
+  import { Breakpoint } from "carbon-components-svelte";
+  import type { BreakpointSize } from "carbon-components-svelte/Breakpoint/breakpoints";
+
+  export let size: BreakpointSize | undefined = undefined;
+  export let sizes: Record<BreakpointSize, boolean> = {
+    sm: false,
+    md: false,
+    lg: false,
+    xlg: false,
+    max: false,
+  };
+</script>
+
+<Breakpoint
+  bind:size
+  bind:sizes
+  on:change
+  let:size={currentSize}
+  let:sizes={currentSizes}
+>
+  <div data-testid="current-size">{currentSize}</div>
+  <div data-testid="is-sm">{currentSizes.sm}</div>
+  <div data-testid="is-md">{currentSizes.md}</div>
+  <div data-testid="is-lg">{currentSizes.lg}</div>
+  <div data-testid="is-xlg">{currentSizes.xlg}</div>
+  <div data-testid="is-max">{currentSizes.max}</div>
+</Breakpoint>