move preset width cycling logic into class

src/lib/behavior/PresetWidths.ts

@@ -5,7 +5,13 @@ class PresetWidths {
         this.presets = PresetWidths.parsePresetWidths(presetWidths, spacing);
     }
 
-    public get(minWidth: number, maxWidth: number) {
+    public next(currentWidth: number, minWidth: number, maxWidth: number) {
+        const widths = this.getWidths(minWidth, maxWidth);
+        const nextIndex = widths.findIndex(width => width > currentWidth);
+        return nextIndex >= 0 ? widths[nextIndex] : widths[0];
+    }
+
+    private getWidths(minWidth: number, maxWidth: number) {
         const widths = this.presets.map(f => clamp(f(maxWidth), minWidth, maxWidth));
         widths.sort((a, b) => a - b);
         return uniq(widths);

src/lib/keyBindings/Actions.ts

@@ -188,10 +188,7 @@ class Actions {
         if (this.config.presetWidths === null) {
             return;
         }
-        const widths = this.config.presetWidths.get(column.getMinWidth(), column.getMaxWidth());
-        const currentWidth = column.getWidth();
-        const nextIndex = widths.findIndex(width => width > currentWidth);
-        const nextWidth = nextIndex >= 0 ? widths[nextIndex] : widths[0];
+        const nextWidth = this.config.presetWidths.next(column.getWidth(), column.getMinWidth(), column.getMaxWidth());
         column.setWidth(nextWidth, true);
     }
 

src/tests/units/behavior/PresetWidths.ts

@@ -23,13 +23,21 @@ tests.register("PresetWidths", 1, () => {
         { str: " ", error: true },
     ];
 
+    function assertWidths(presetWidths: PresetWidths, expectedWidths: number[]) {
+        let currentWidth = 0;
+        for (const expectedWidth of expectedWidths) {
+            currentWidth = presetWidths.next(currentWidth, minWidth, maxWidth);
+            Assert.equal(currentWidth, expectedWidth);
+        }
+        const repeatedWidth = presetWidths.next(currentWidth, minWidth, maxWidth);
+        Assert.equal(repeatedWidth, expectedWidths[0]);
+    }
+
     for (const testCase of testCases) {
         try {
             const presetWidths = new PresetWidths(testCase.str, spacing);
             Assert.truth(!testCase.error);
-
-            const result = presetWidths.get(minWidth, maxWidth);
-            Assert.equalArrays(result, testCase.result!);
+            assertWidths(presetWidths, testCase.result!);
         } catch (error) {
             Assert.truth(testCase.error === true);
         }

src/tests/utils/Assert.ts

@@ -68,20 +68,6 @@ namespace Assert {
         );
     }
 
-    export function equalArrays(
-        actual: any[],
-        expected: any[],
-        { message, skip=0 }: Options = {},
-    ) {
-        truth(
-            actual.length === expected.length && actual.every((item, index) => item === expected[index]),
-            {
-                message: buildMessage(actual, expected, "Arrays not equal", message),
-                skip: skip + 1,
-            },
-        );
-    }
-
     export function equalRects(
         actual: QmlRect,
         expected: QmlRect,