test: cover ViewTest and run

2026-09-10 19:42:20 +02:00
1 parent 4682431a80
commit 03072818c2
@@ -0,0 +1,157 @@
+package kestrel
+
+import kestrel.catalog.Catalog
+import kestrel.engine.CreateViewResult
+import kestrel.engine.DropViewResult
+import kestrel.engine.Executor
+import kestrel.engine.SelectResult
+import kestrel.engine.StatementResult
+import kestrel.sql.lexer.Lexer
+import kestrel.sql.parser.Parser
+import kestrel.storage.Value
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import kotlin.test.assertTrue
+
+class ViewTest {
+    private val catalog = Catalog()
+    private val executor = Executor(catalog)
+
+    private fun run(sql: String): List<StatementResult> =
+        Parser(Lexer(sql).tokenize()).parseProgram().map { executor.execute(it) }
+
+    private fun exec(sql: String): StatementResult = run(sql).single()
+
+    private fun select(sql: String): SelectResult = exec(sql) as SelectResult
+
+    private fun int(value: Long) = Value.IntegerValue(value)
+    private fun text(value: String) = Value.TextValue(value)
+
+    private fun seedUsers() {
+        run("CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT NOT NULL, age INTEGER, dept TEXT)")
+        run(
+            "INSERT INTO users VALUES " +
+                "(1, 'ada', 36, 'eng'), (2, 'linus', 54, 'eng'), (3, 'grace', 85, 'navy'), (4, 'alan', 41, NULL)"
+        )
+    }
+
+    @Test
+    fun createViewReturnsResultAndRegistersName() {
+        seedUsers()
+        val result = exec("CREATE VIEW adults AS SELECT id, name FROM users WHERE age >= 40") as CreateViewResult
+        assertEquals("adults", result.viewName)
+        assertEquals(listOf("adults"), catalog.viewNames)
+    }
+
+    @Test
+    fun queryingAViewRunsItsDefiningQueryFresh() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id, name FROM users WHERE age >= 40")
+        val first = select("SELECT name FROM adults ORDER BY id ASC")
+        assertEquals(listOf(text("linus"), text("grace"), text("alan")), first.rows.map { it.single() })
+
+        run("INSERT INTO users VALUES (5, 'margaret', 61, 'navy')")
+        val second = select("SELECT name FROM adults ORDER BY id ASC")
+        assertEquals(
+            listOf(text("linus"), text("grace"), text("alan"), text("margaret")),
+            second.rows.map { it.single() }
+        )
+    }
+
+    @Test
+    fun viewCanBeUsedAsAJoinTarget() {
+        seedUsers()
+        run("CREATE TABLE bonuses (dept TEXT, amount INTEGER)")
+        run("INSERT INTO bonuses VALUES ('eng', 1000), ('navy', 500)")
+        run("CREATE VIEW eng_staff AS SELECT id, name, dept FROM users WHERE dept = 'eng'")
+        val result = select(
+            "SELECT eng_staff.name, bonuses.amount FROM eng_staff " +
+                "JOIN bonuses ON eng_staff.dept = bonuses.dept ORDER BY eng_staff.id ASC"
+        )
+        assertEquals(
+            listOf(listOf(text("ada"), int(1000)), listOf(text("linus"), int(1000))),
+            result.rows
+        )
+    }
+
+    @Test
+    fun viewOverAggregateQueryWorks() {
+        seedUsers()
+        run("CREATE VIEW dept_counts AS SELECT dept, COUNT(*) AS n FROM users GROUP BY dept")
+        val result = select("SELECT dept, n FROM dept_counts WHERE n > 1 ORDER BY dept ASC")
+        assertEquals(listOf(listOf(text("eng"), int(2))), result.rows)
+    }
+
+    @Test
+    fun viewDefinitionCanReferenceAnotherView() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id, name, age FROM users WHERE age >= 40")
+        run("CREATE VIEW seniors AS SELECT id, name FROM adults WHERE age >= 60")
+        val result = select("SELECT name FROM seniors")
+        assertEquals(listOf(listOf(text("grace"))), result.rows)
+    }
+
+    @Test
+    fun creatingAViewValidatesColumnsEagerly() {
+        seedUsers()
+        assertFailsWith<KestrelException> { run("CREATE VIEW broken AS SELECT nope FROM users") }
+        assertTrue(catalog.viewNames.isEmpty())
+    }
+
+    @Test
+    fun creatingAViewOverAnUnknownTableFails() {
+        assertFailsWith<KestrelException> { run("CREATE VIEW v AS SELECT * FROM missing") }
+    }
+
+    @Test
+    fun duplicateViewNameFailsWithoutOrReplace() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        assertFailsWith<KestrelException> { run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 21") }
+    }
+
+    @Test
+    fun createOrReplaceViewSwapsTheDefinition() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        run("CREATE OR REPLACE VIEW adults AS SELECT id FROM users WHERE age >= 50")
+        val result = select("SELECT id FROM adults ORDER BY id ASC")
+        assertEquals(listOf(listOf(int(2)), listOf(int(3))), result.rows)
+    }
+
+    @Test
+    fun dropViewRemovesItAndItStopsBeingQueryable() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        val result = exec("DROP VIEW adults") as DropViewResult
+        assertEquals("adults", result.viewName)
+        assertFailsWith<KestrelException> { run("SELECT * FROM adults") }
+    }
+
+    @Test
+    fun droppingAnUnknownViewFails() {
+        assertFailsWith<KestrelException> { run("DROP VIEW nope") }
+    }
+
+    @Test
+    fun cannotCreateTableWithSameNameAsAnExistingView() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        assertFailsWith<KestrelException> { run("CREATE TABLE adults (id INTEGER)") }
+    }
+
+    @Test
+    fun cannotCreateViewWithSameNameAsAnExistingTable() {
+        seedUsers()
+        assertFailsWith<KestrelException> { run("CREATE VIEW users AS SELECT id FROM users") }
+    }
+
+    @Test
+    fun dropTableRefusesAViewNameAndDropViewRefusesATableName() {
+        seedUsers()
+        run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        assertFailsWith<KestrelException> { run("DROP TABLE adults") }
+        assertFailsWith<KestrelException> { run("DROP VIEW users") }
+    }
+