Add test for StudentDao

app/src/test/java/io/github/wulkanowy/data/db/dao/StudentDaoTest.kt

@@ -0,0 +1,103 @@
+package io.github.wulkanowy.data.db.dao
+
+import android.content.Context
+import android.os.Build
+import androidx.room.Room
+import androidx.test.core.app.ApplicationProvider
+import dagger.hilt.android.testing.HiltTestApplication
+import io.github.wulkanowy.data.db.AppDatabase
+import io.github.wulkanowy.getSemesterEntity
+import io.github.wulkanowy.getStudentEntity
+import kotlinx.coroutines.test.runTest
+import org.junit.After
+import org.junit.Before
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [Build.VERSION_CODES.O_MR1], application = HiltTestApplication::class)
+class StudentDaoTest {
+
+    private lateinit var studentDao: StudentDao
+    private lateinit var semesterDao: SemesterDao
+    private lateinit var db: AppDatabase
+
+    @Before
+    fun createDb() {
+        val context: Context = ApplicationProvider.getApplicationContext()
+        db = Room.inMemoryDatabaseBuilder(
+            context = context,
+            klass = AppDatabase::class.java
+        ).build()
+        studentDao = db.studentDao
+        semesterDao = db.semesterDao
+    }
+
+    @Test
+    fun `get students associated with correct semester`() = runTest {
+        val notEduOneStudent = getStudentEntity()
+            .copy(
+                isEduOne = false,
+                classId = 42,
+                studentId = 100
+            )
+            .apply { id = 1 }
+        val eduOneStudent = getStudentEntity()
+            .copy(
+                isEduOne = true,
+                classId = 0,
+                studentId = 100
+            )
+            .apply { id = 2 }
+
+        val semesterAssociatedWithNotEduOneStudent = getSemesterEntity()
+            .copy(
+                studentId = notEduOneStudent.studentId,
+                classId = notEduOneStudent.classId,
+                diaryId = 1 // make semester unique
+            )
+            .apply { id = 0 }
+        val semesterAssociatedWithEduOneStudent = getSemesterEntity()
+            .copy(
+                studentId = eduOneStudent.studentId,
+                classId = eduOneStudent.classId,
+                diaryId = 2 // make semester unique
+            )
+            .apply { id = 0 }
+
+        studentDao.insertAll(listOf(notEduOneStudent, eduOneStudent))
+        semesterDao.insertAll(
+            listOf(
+                semesterAssociatedWithNotEduOneStudent,
+                semesterAssociatedWithEduOneStudent
+            )
+        )
+
+        val studentsWithSemesters = studentDao.loadStudentsWithSemesters()
+        val notEduOneSemestersResult = studentsWithSemesters.entries
+            .find { (student, _) -> student.id == notEduOneStudent.id }
+            ?.value
+        val eduOneSemestersResult = studentsWithSemesters.entries
+            .find { (student, _) -> student.id == eduOneStudent.id }
+            ?.value
+
+        assertEquals(2, studentsWithSemesters.size)
+
+        assertEquals(1, notEduOneSemestersResult?.size)
+        assertEquals(1, eduOneSemestersResult?.size)
+
+        assertEquals(semesterAssociatedWithEduOneStudent, eduOneSemestersResult?.firstOrNull())
+        assertEquals(
+            semesterAssociatedWithNotEduOneStudent,
+            notEduOneSemestersResult?.firstOrNull()
+        )
+    }
+
+    @After
+    fun closeDb() {
+        db.close()
+    }
+}