🧪 test(api): Exhaustive testing of from on small iterables.

Author: make-github-pseudonymous-again

package.json

@@ -78,6 +78,7 @@
     "@iterable-iterator/list": "1.0.1",
     "@iterable-iterator/map": "1.0.1",
     "@iterable-iterator/range": "2.1.0",
+    "@iterable-iterator/reduce": "^1.0.1",
     "@iterable-iterator/repeat": "1.0.1",
     "@iterable-iterator/reversed": "1.0.0",
     "@iterable-iterator/tee": "2.0.0",

test/src/_fixtures.js

@@ -0,0 +1,34 @@
+import {map} from '@iterable-iterator/map';
+import {reduce} from '@iterable-iterator/reduce';
+
+import {Measures} from '@functional-abstraction/measure';
+
+export const ABSTRACT_COUNTER = Measures.COUNTER;
+
+export const FAST_COUNTER = {
+	plus(a, b) {
+		return a + b;
+	},
+	measure(_x) {
+		return 1;
+	},
+	zero() {
+		return 0;
+	},
+};
+
+export const measure = (M, iterable) =>
+	reduce(M.plus.bind(M), map(M.measure.bind(M), iterable), M.zero());
+
+export const measureToString = (M) => {
+	switch (M) {
+		case FAST_COUNTER:
+			return 'COUNTER(FAST)';
+		case ABSTRACT_COUNTER:
+			return 'COUNTER(ABSTRACT)';
+		default:
+			throw new Error(`unknown measure ${M.name}`);
+	}
+};
+
+export const iterableToString = (iterable) => iterable.toString();

test/src/regression/fast/from_medium_list.js

@@ -0,0 +1,32 @@
+import test from 'ava';
+
+import {range} from '@iterable-iterator/range';
+import {tee} from '@iterable-iterator/tee';
+
+import {
+	ABSTRACT_COUNTER as COUNTER,
+	measure,
+	measureToString,
+	iterableToString,
+} from '../../_fixtures.js';
+
+import {from} from '../../../../src/index.js';
+
+const cover = (t, M, iterable) => {
+	const [copy1, copy2, copy3] = tee(iterable, 3);
+
+	const tree = from(M, copy1);
+
+	const expectedMeasure = measure(M, copy2);
+	t.is(tree.measure(), expectedMeasure);
+
+	const expectedContents = Array.from(copy3);
+	t.deepEqual(Array.from(tree), expectedContents);
+};
+
+cover.title = (title, M, iterable) =>
+	title ?? `${measureToString(M)} ${iterableToString(iterable)}`;
+
+for (const i of range(145)) {
+	test(cover, COUNTER, range(i));
+}