diff --git a/test/test_ast.ml b/test/test_ast.ml
index e72ab4a..4e366f4 100644
--- a/test/test_ast.ml
+++ b/test/test_ast.ml
@@ -10,13 +10,208 @@ let equal_ast ast1 ast2 =
 let query_testable =
   Alcotest.testable Ast.pp_query equal_ast
 
-let test_simple_select() =
+let test_simple_select () =
   let q1 = parse "SELECT a FROM t" in
-  let ast1 = Query(Select([Column("a")], [Table("t")])) in
-  Alcotest.(check query_testable) "Ok" q1 ast1 
+  let ast1 = Query(Select([Column("a")], [Table("t")], None)) in
+  Alcotest.(check query_testable) "Ok" q1 ast1;
+
+  let q2 = parse "SELECT * FROM t" in
+  let ast2 = Query(Select([Asterisk], [Table("t")], None)) in
+  Alcotest.(check query_testable) "Ok2" q2 ast2 
+
+let test_default_join () =
+  let q1 = parse "SELECT a FROM t1 JOIN t2 ON a = b" in
+  let ast1 = Query(
+    Select(
+      [Column("a")],
+      [Join(
+        Table("t1"), 
+        Left, 
+        Table("t2"),
+        Some(
+          Condition(
+            "a",
+            Comparison(Equals, "b")
+          )
+        )
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_left_join () = 
+  let q1 = parse "SELECT a FROM t1 LEFT JOIN t2 ON a = b" in
+  let ast1 = Query(
+    Select([Column("a")], 
+      [Join(
+        Table("t1"), 
+        Left, 
+        Table("t2"),
+        Some(
+          Condition(
+            "a",
+            Comparison(Equals, "b")
+          )
+        )
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+  
+let test_right_join () = 
+  let q1 = parse "SELECT a FROM t1 RIGHT JOIN t2 ON a = b" in
+  let ast1 = Query(
+    Select([Column("a")], 
+      [Join(
+        Table("t1"), 
+        Right, 
+        Table("t2"),
+        Some(
+          Condition(
+            "a",
+            Comparison(Equals, "b")
+          )
+        )
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_inner_join () = 
+  let q1 = parse "SELECT a FROM t1 INNER JOIN t2 ON a = b" in
+  let ast1 = Query(
+    Select([Column("a")], 
+      [Join(
+        Table("t1"), 
+        Inner, 
+        Table("t2"),
+        Some(
+          Condition(
+            "a",
+            Comparison(Equals, "b")
+          )
+        )
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_union_join () = 
+  let q1 = parse "SELECT a FROM t1 UNION JOIN t2" in
+  let ast1 = Query(
+    Select([Column("a")], 
+      [Join(
+        Table("t1"), 
+        Union, 
+        Table("t2"),
+        None
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_cross_join () = 
+  let q1 = parse "SELECT a FROM t1 CROSS JOIN t2" in
+  let ast1 = Query(
+    Select([Column("a")], 
+      [Join(
+        Table("t1"), 
+        Cross, 
+        Table("t2"),
+        None
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_natural_join () = 
+  let q1 = parse "SELECT a FROM t1 NATURAL JOIN t2" in
+  let ast1 = Query(
+    Select([Column("a")],
+      [Join(
+        Table("t1"), 
+        Natural, 
+        Table("t2"),
+        None
+      )],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_join_join () = 
+  let q1 = parse "SELECT a FROM t1 JOIN t2 ON a = b JOIN t3 ON a = c" in
+  let ast1 = Query(
+    Select([Column("a")], [
+      Join(
+        Join(
+          Table("t1"), 
+          Left, 
+          Table("t2"),
+          Some(
+            Condition(
+              "a",
+              Comparison(Equals, "b")
+            )
+          ) 
+        ),
+        Left,
+        Table("t3"),
+        Some(
+          Condition(
+            "a",
+            Comparison(Equals, "c")
+          )
+        )
+      )
+    ],
+    None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
+
+let test_where_equals () = 
+  let q1 = parse "SELECT a FROM t1 WHERE a = a OR a = b" in
+  let ast1 = Query(
+    Select(
+      [Column("a")],
+      [Table("t1")],
+      None
+    )
+  ) in
+  Alcotest.(check query_testable) "Ok" q1 ast1
 
 let simple_select_set  = [ ("Equals", `Quick, test_simple_select) ]
 
+let simple_join_set = [
+  ("Default Join", `Quick, test_default_join);
+  ("Left Join", `Quick, test_left_join);
+  ("Right Join", `Quick, test_right_join);
+  ("Inner Join", `Quick, test_inner_join);
+  ("Union Join", `Quick, test_union_join);
+  ("Cross Join", `Quick, test_cross_join);
+  ("Natural Join", `Quick, test_natural_join)
+]
+
+let multiple_joins_set = [ 
+  ("Join Join", `Quick, test_join_join)
+]
+
+let where_clauses_set = [
+  ("Where Equals", `Quick, test_where_equals)
+]
+
 let () =
   Alcotest.run "Ast tests"
-    [ ("Simple Selects", simple_select_set) ]
+    [
+      ("Simple Selects", simple_select_set); 
+      ("Simple Joins", simple_join_set);
+      ("Multiple Joins", multiple_joins_set);
+      ("Where Clauses", where_clauses_set)
+    ]