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diff --git a/src/3rdparty/2geom/tests/polynomial-test.cpp b/src/3rdparty/2geom/tests/polynomial-test.cpp
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+/** @file
+ * @brief Unit tests for Polynomial and related functions.
+ * Uses the Google Testing Framework
+ *//*
+ * Authors:
+ *   Krzysztof Kosiński <tweenk.pl@gmail.com>
+ *
+ * Copyright 2015-2019 Authors
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (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.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ */
+
+#include "testing.h"
+#include <iostream>
+#include <glib.h>
+
+#include <2geom/polynomial.h>
+
+using namespace Geom;
+
+TEST(PolynomialTest, SolveQuadratic) {
+    for (unsigned i = 0; i < 1000; ++i) {
+        Coord x1 = g_random_double_range(-100, 100);
+        Coord x2 = g_random_double_range(-100, 100);
+
+        Coord a = g_random_double_range(-10, 10);
+        Coord b = -a * (x1 + x2);
+        Coord c = a * x1 * x2;
+
+        std::vector<Coord> result = solve_quadratic(a, b, c);
+
+        EXPECT_EQ(result.size(), 2u);
+        if (x1 < x2) {
+            EXPECT_FLOAT_EQ(result[0], x1);
+            EXPECT_FLOAT_EQ(result[1], x2);
+        } else {
+            EXPECT_FLOAT_EQ(result[0], x2);
+            EXPECT_FLOAT_EQ(result[1], x1);
+        }
+    }
+}
+
+TEST(PolynomialTest, SolvePathologicalQuadratic) {
+    std::vector<Coord> r;
+
+    r = solve_quadratic(1, -1e9, 1);
+    ASSERT_EQ(r.size(), 2u);
+    EXPECT_FLOAT_EQ(r[0], 1e-9);
+    EXPECT_FLOAT_EQ(r[1], 1e9);
+
+    r = solve_quadratic(1, -4, 3.999999);
+    ASSERT_EQ(r.size(), 2u);
+    EXPECT_FLOAT_EQ(r[0], 1.999);
+    EXPECT_FLOAT_EQ(r[1], 2.001);
+
+    r = solve_quadratic(1, 0, -4);
+    ASSERT_EQ(r.size(), 2u);
+    EXPECT_FLOAT_EQ(r[0], -2);
+    EXPECT_FLOAT_EQ(r[1], 2);
+
+    r = solve_quadratic(1, 0, -16);
+    ASSERT_EQ(r.size(), 2u);
+    EXPECT_FLOAT_EQ(r[0], -4);
+    EXPECT_FLOAT_EQ(r[1], 4);
+
+    r = solve_quadratic(1, 0, -100);
+    ASSERT_EQ(r.size(), 2u);
+    EXPECT_FLOAT_EQ(r[0], -10);
+    EXPECT_FLOAT_EQ(r[1], 10);
+}
+
+TEST(PolynomialTest, SolveCubic) {
+    for (unsigned i = 0; i < 1000; ++i) {
+        Coord x1 = g_random_double_range(-100, 100);
+        Coord x2 = g_random_double_range(-100, 100);
+        Coord x3 = g_random_double_range(-100, 100);
+
+        Coord a = g_random_double_range(-10, 10);
+        Coord b = -a * (x1 + x2 + x3);
+        Coord c = a * (x1*x2 + x2*x3 + x1*x3);
+        Coord d = -a * x1 * x2 * x3;
+
+        std::vector<Coord> result = solve_cubic(a, b, c, d);
+        std::vector<Coord> x(3); x[0] = x1; x[1] = x2; x[2] = x3;
+        std::sort(x.begin(), x.end());
+
+        ASSERT_EQ(result.size(), 3u);
+        EXPECT_FLOAT_EQ(result[0], x[0]);
+        EXPECT_FLOAT_EQ(result[1], x[1]);
+        EXPECT_FLOAT_EQ(result[2], x[2]);
+    }
+
+    // corner cases
+    // (x^2 + 7)(x - 2)
+    std::vector<Coord> r1 = solve_cubic(1, -2, 7, -14);
+    EXPECT_EQ(r1.size(), 1u);
+    EXPECT_FLOAT_EQ(r1[0], 2);
+
+    // (x + 1)^2 (x-2)
+    std::vector<Coord> r2 = solve_cubic(1, 0, -3, -2);
+    ASSERT_EQ(r2.size(), 3u);
+    EXPECT_FLOAT_EQ(r2[0], -1);
+    EXPECT_FLOAT_EQ(r2[1], -1);
+    EXPECT_FLOAT_EQ(r2[2], 2);
+}