Unit Test Cold Flow Take

Unit Test Cold Flow Take.kt

    /**
     * Unit Testing Cold Flows the Android recommended way
     */

    @Test
    fun `cold flow - take multiple - Android recommended - Success!`() {
        runBlocking {
            val actual = mutableListOf<String>()
            flow {
                emit("test")
                emit("test")
            }.take(2).collect {
                actual.add(it)
            }
            assertThat(actual).containsExactly("test", "test")
        }
    }

    @Test
    fun `cold flow - take too little - Android recommended - Success! Oh no!`() {
        runBlocking {
            val actual = mutableListOf<String>()
            flow {
                emit("test")
                emit("test")
                emit("test") // Added an extra emission, simulating an implementation change
            }.take(2).collect {
                actual.add(it)
            }
            assertThat(actual).containsExactly("test", "test") // We want this to fail!
        }
    }

    @Test
    fun `cold flow - take too much - Android recommended way - Fails!`() {
        runBlocking {
            val actual = mutableListOf<String>()
            flow {
                emit("test")
                // Deleted the second emission, simulating an implementation change
            }.take(2).collect {
                actual.add(it)
            }
            assertThat(actual).containsExactly("test", "test") // We want this to fail!
        }
    }