1 files changed, 104 insertions, 0 deletions
diff --git a/ink_stroke_modeler/internal/wobble_smoother_test.cc b/ink_stroke_modeler/internal/wobble_smoother_test.cc
new file mode 100644
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--- /dev/null
+++ b/ink_stroke_modeler/internal/wobble_smoother_test.cc
@@ -0,0 +1,104 @@
+// Copyright 2022 Google LLC
+//
+// Licensed 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.
+
+#include "ink_stroke_modeler/internal/wobble_smoother.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "ink_stroke_modeler/internal/type_matchers.h"
+#include "ink_stroke_modeler/params.h"
+#include "ink_stroke_modeler/types.h"
+
+namespace ink {
+namespace stroke_model {
+namespace {
+
+const WobbleSmootherParams kDefaultParams{
+    .timeout = Duration(.04), .speed_floor = 1.31, .speed_ceiling = 1.44};
+
+TEST(WobbleSmootherTest, SlowStraightLine) {
+  // The line moves at 1 cm/s, which is below the floor of 1.31 cm/s.
+  WobbleSmoother filter;
+  filter.Reset(kDefaultParams, {3, 4}, Time{1});
+  EXPECT_THAT(filter.Update({3.016, 4}, Time{1.016}), Vec2Eq({3.008, 4}));
+  EXPECT_THAT(filter.Update({3.032, 4}, Time{1.032}), Vec2Eq({3.016, 4}));
+  EXPECT_THAT(filter.Update({3.048, 4}, Time{1.048}), Vec2Eq({3.032, 4}));
+  EXPECT_THAT(filter.Update({3.064, 4}, Time{1.064}), Vec2Eq({3.048, 4}));
+}
+
+TEST(WobbleSmootherTest, SlowStraightLineEqualFloorAndCeiling) {
+  // The line moves at 1 cm/s, which is below the floor of 1.31 cm/s.
+  WobbleSmootherParams equal_floor_and_ceiling_params{
+      .timeout = Duration(.04), .speed_floor = 1.31, .speed_ceiling = 1.31};
+  WobbleSmoother filter;
+  filter.Reset(equal_floor_and_ceiling_params, {3, 4}, Time{1});
+  EXPECT_THAT(filter.Update({3.016, 4}, Time{1.016}), Vec2Eq({3.008, 4}));
+  EXPECT_THAT(filter.Update({3.032, 4}, Time{1.032}), Vec2Eq({3.016, 4}));
+  EXPECT_THAT(filter.Update({3.048, 4}, Time{1.048}), Vec2Eq({3.032, 4}));
+  EXPECT_THAT(filter.Update({3.064, 4}, Time{1.064}), Vec2Eq({3.048, 4}));
+}
+
+TEST(WobbleSmootherTest, FastStraightLine) {
+  // The line moves at 1.5 cm/s, which is above the ceiling of 1.44 cm/s.
+  WobbleSmoother filter;
+  filter.Reset(kDefaultParams, {-1, 0}, Time{0});
+  EXPECT_THAT(filter.Update({-1, .024}, Time{.016}), Vec2Eq({-1, .024}));
+  EXPECT_THAT(filter.Update({-1, .048}, Time{.032}), Vec2Eq({-1, .048}));
+  EXPECT_THAT(filter.Update({-1, .072}, Time{.048}), Vec2Eq({-1, .072}));
+}
+
+TEST(WobbleSmootherTest, FastStraightLineEqualFloorAndCeiling) {
+  // The line moves at 1.5 cm/s, which is above the ceiling of 1.44 cm/s.
+  WobbleSmoother filter;
+  WobbleSmootherParams equal_floor_and_ceiling_params{
+      .timeout = Duration(.04), .speed_floor = 1.41, .speed_ceiling = 1.41};
+  filter.Reset(equal_floor_and_ceiling_params, {-1, 0}, Time{0});
+  EXPECT_THAT(filter.Update({-1, .024}, Time{.016}), Vec2Eq({-1, .024}));
+  EXPECT_THAT(filter.Update({-1, .048}, Time{.032}), Vec2Eq({-1, .048}));
+  EXPECT_THAT(filter.Update({-1, .072}, Time{.048}), Vec2Eq({-1, .072}));
+}
+
+TEST(WobbleSmootherTest, SlowZigZag) {
+  // The line moves at 1 cm/s, which is below the floor of 1.31 cm/s.
+  WobbleSmoother filter;
+  filter.Reset(kDefaultParams, {1, 2}, Time{5});
+  EXPECT_THAT(filter.Update({1.016, 2}, Time{5.016}), Vec2Eq({1.008, 2}));
+  EXPECT_THAT(filter.Update({1.016, 2.016}, Time{5.032}),
+              Vec2Eq({1.0106667, 2.0053333}));
+  EXPECT_THAT(filter.Update({1.032, 2.016}, Time{5.048}),
+              Vec2Eq({1.0213333, 2.0106667}));
+  EXPECT_THAT(filter.Update({1.032, 2.032}, Time{5.064}),
+              Vec2Eq({1.0266667, 2.0213333}));
+  EXPECT_THAT(filter.Update({1.048, 2.032}, Time{5.080}),
+              Vec2Eq({1.0373333, 2.0266667}));
+  EXPECT_THAT(filter.Update({1.048, 2.048}, Time{5.096}),
+              Vec2Eq({1.0426667, 2.0373333}));
+}
+
+TEST(WobbleSmootherTest, FastZigZag) {
+  // The line moves at 1.5 cm/s, which is above the ceiling of 1.44 cm/s.
+  WobbleSmoother filter;
+  filter.Reset(kDefaultParams, {7, 3}, Time{8});
+  EXPECT_THAT(filter.Update({7, 3.024}, Time{8.016}), Vec2Eq({7, 3.024}));
+  EXPECT_THAT(filter.Update({7.024, 3.024}, Time{8.032}),
+              Vec2Eq({7.024, 3.024}));
+  EXPECT_THAT(filter.Update({7.024, 3.048}, Time{8.048}),
+              Vec2Eq({7.024, 3.048}));
+  EXPECT_THAT(filter.Update({7.048, 3.048}, Time{8.064}),
+              Vec2Eq({7.048, 3.048}));
+}
+
+}  // namespace
+}  // namespace stroke_model
+}  // namespace ink