[counter] Add persistent counter sensor (#19746)

tests/components/counter/sensor/test_counter.cpp

@@ -0,0 +1,84 @@
+#include "../common.h"
+
+namespace esphome::counter::testing {
+
+TEST_F(CounterTest, StartsAtZero) {
+  this->counter_.setup();
+  EXPECT_EQ(this->counter_.state, 0.0f);
+}
+
+TEST(CounterInitialValue, PublishedAtSetupWhenNotRestoring) {
+  CounterSensor counter(false, -12);
+  counter.setup();
+  EXPECT_EQ(counter.state, -12.0f);
+  counter.increment();
+  EXPECT_EQ(counter.state, -11.0f);
+}
+
+TEST_F(CounterTest, SetValuePublishesState) {
+  this->counter_.set_value(42);
+  EXPECT_EQ(this->counter_.state, 42.0f);
+}
+
+TEST_F(CounterTest, IncrementDefaultsToOne) {
+  this->counter_.increment();
+  this->counter_.increment();
+  EXPECT_EQ(this->counter_.state, 2.0f);
+}
+
+TEST_F(CounterTest, IncrementAcceptsNegativeAmounts) {
+  this->counter_.set_value(10);
+  this->counter_.increment(-25);
+  EXPECT_EQ(this->counter_.state, -15.0f);
+}
+
+TEST_F(CounterTest, ValueBeyondInt32) {
+  this->counter_.set_value(5000000000LL);
+  this->counter_.increment(5000000000LL);
+  EXPECT_EQ(this->counter_.state, 1.0e10f);
+}
+
+TEST_F(CounterTest, IncrementWrapsAtInt64Limits) {
+  this->counter_.set_value(INT64_MAX_VALUE);
+  this->counter_.increment(1);
+  EXPECT_EQ(this->counter_.state, static_cast<float>(INT64_MIN_VALUE));
+
+  this->counter_.set_value(INT64_MIN_VALUE);
+  this->counter_.increment(-1);
+  EXPECT_EQ(this->counter_.state, static_cast<float>(INT64_MAX_VALUE));
+}
+
+TEST_F(CounterTest, CountsEachPublishFromSource) {
+  sensor::Sensor source;
+  this->counter_.count_updates_from(&source);
+
+  // The counted value is unrelated to what the source publishes.
+  source.publish_state(10.0f);
+  source.publish_state(10.0f);
+  source.publish_state(-3.5f);
+  EXPECT_EQ(this->counter_.state, 3.0f);
+}
+
+TEST_F(CounterTest, SourceUpdatesAddToCurrentValue) {
+  sensor::Sensor source;
+  this->counter_.count_updates_from(&source);
+
+  this->counter_.set_value(100);
+  source.publish_state(1.0f);
+  EXPECT_EQ(this->counter_.state, 101.0f);
+}
+
+TEST_F(CounterTest, CountsOnlyTrueFromBinarySource) {
+  FakeBinarySource source;
+  this->counter_.count_true_from(&source);
+
+  source.publish(true);
+  source.publish(false);
+  EXPECT_EQ(this->counter_.state, 1.0f);
+  source.publish(true);
+  source.publish(false);
+  source.publish(false);
+  EXPECT_EQ(this->counter_.state, 2.0f);
+}
+
+}  // namespace esphome::counter::testing