1 files changed, 80 insertions, 0 deletions
diff --git a/src/arrow/js/test/unit/table/assign-tests.ts b/src/arrow/js/test/unit/table/assign-tests.ts
new file mode 100644
index 000000000..fa1dacbc6
--- /dev/null
+++ b/src/arrow/js/test/unit/table/assign-tests.ts
@@ -0,0 +1,80 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+/* eslint-disable jest/no-standalone-expect */
+
+import '../../jest-extensions';
+import { zip } from 'ix/iterable';
+import * as generate from '../../generate-test-data';
+import { validateTable } from '../generated-data-validators';
+import {
+    Schema, Field, DataType, Int32, Float32, Utf8
+} from 'apache-arrow';
+
+const toSchema = (...xs: [string, DataType][]) => new Schema(xs.map((x) => new Field(...x)));
+const schema1             = toSchema(['a', new Int32()], ['b', new Float32()], ['c', new Utf8()]);
+const partialOverlapWith1 = toSchema(['a', new Int32()], ['b', new Float32()], ['f', new Utf8()]);
+const schema2             = toSchema(['d', new Int32()], ['e', new Float32()], ['f', new Utf8()]);
+
+describe('Table.assign()', () => {
+    describe(`should assign non-overlapping fields`, () => {
+        const lhs = generate.table([20], schema1);
+        const rhs = generate.table([20], schema2);
+        const table = lhs.table.assign(rhs.table);
+        const f = assignGeneratedTables(lhs, rhs);
+        expect(table.schema.fields.map((f) => f.name)).toEqual(['a', 'b', 'c', 'd', 'e', 'f']);
+        validateTable({ ...f([0,1,2], [3,4,5]), table }).run();
+    });
+    describe(`should assign partially-overlapping fields`, () => {
+        const lhs = generate.table([20], schema1);
+        const rhs = generate.table([20], partialOverlapWith1);
+        const table = lhs.table.assign(rhs.table);
+        const f = assignGeneratedTables(lhs, rhs);
+        expect(table.schema.fields.map((f) => f.name)).toEqual(['a', 'b', 'c', 'f']);
+        // eslint-disable-next-line no-sparse-arrays
+        validateTable({ ...f([ , , 2], [0,1,3]), table }).run();
+    });
+    describe(`should assign completely-overlapping fields`, () => {
+        const lhs = generate.table([20], schema2);
+        const rhs = generate.table([20], schema2);
+        const table = lhs.table.assign(rhs.table);
+        const f = assignGeneratedTables(lhs, rhs);
+        expect(table.schema.fields.map((f) => f.name)).toEqual(['d', 'e', 'f']);
+        // eslint-disable-next-line no-sparse-arrays
+        validateTable({ ...f([ , , ], [0,1,2]), table }).run();
+    });
+});
+
+function assignGeneratedTables(lhs: generate.GeneratedTable, rhs: generate.GeneratedTable) {
+    return function createAssignedTestData(lhsIndices: any[], rhsIndices: any[]) {
+        const pluckLhs = (xs: any[], ys: any[] = []) => lhsIndices.reduce((ys, i, j) => {
+            if (i !== undefined) { ys[i] = xs ? xs[j] : null; }
+            return ys;
+        }, ys);
+        const pluckRhs = (xs: any[], ys: any[] = []) => rhsIndices.reduce((ys, i, j) => {
+            if (i !== undefined) { ys[i] = xs ? xs[j] : null; }
+            return ys;
+        }, ys);
+        const cols = () => [...pluckLhs(lhs.cols(), pluckRhs(rhs.cols()))];
+        const keys = () => [...pluckLhs(lhs.keys(), pluckRhs(rhs.keys()))];
+        const rows = () => [...zip(lhs.rows(), rhs.rows())].map(([x, y]) => [...pluckLhs(x, pluckRhs(y))]);
+        const colBatches = [...zip(lhs.colBatches, rhs.colBatches)].map(([x, y]) => () => [...pluckLhs(x(), pluckRhs(y()))]);
+        const keyBatches = [...zip(lhs.keyBatches, rhs.keyBatches)].map(([x, y]) => () => [...pluckLhs(x(), pluckRhs(y()))]);
+        const rowBatches = [...zip(lhs.rowBatches, rhs.rowBatches)].map(([x, y]) => () => [...zip(x(), y())].map(([x, y]) => [...pluckLhs(x, pluckRhs(y))]));
+        return { cols, keys, rows, colBatches, keyBatches, rowBatches };
+    };
+}