diff --git a/tests/conditionals.bish b/tests/conditionals.bish
new file mode 100644
index 0000000..09b9a15
--- /dev/null
+++ b/tests/conditionals.bish
@@ -0,0 +1,35 @@
+def test() {
+    x = 0
+    y = 1
+    if (y == 1) {
+        x = 2
+    }
+    assert(x == 2)
+
+    if (y == 2) {
+        x = 3
+    }
+    assert(x == 2)
+
+    if (y == 0) {
+        x = 0
+    } else if (y == 1) {
+        x = 1
+    }
+    assert(x == 1)
+
+    for (i in 0 .. 3) {
+        if (i == 0) {
+            assert(i == 0)
+        } else if (i == 1) {
+            assert(i == 1)
+        } else if (i == 2) {
+            assert(i == 2)
+        } else {
+            assert(i == 3)
+        }
+    }
+    println("Conditional tests passed.")
+}
+
+test()
\ No newline at end of file
diff --git a/tests/return_vals.bish b/tests/return_vals.bish
new file mode 100644
index 0000000..a53b2b1
--- /dev/null
+++ b/tests/return_vals.bish
@@ -0,0 +1,24 @@
+# Tests for return values.
+
+def lastchar(x) {
+    if (x != "") {
+        y = @(echo -ne "$x" | tail -c 1)
+        x = "$y"
+    }
+    return x
+}
+
+def test() {
+    h = lastchar("hello")
+    assert(h == "o")
+    assert(lastchar("hello") == "o")
+    assert(lastchar("") == "")
+    println("Return value tests passed.")
+}
+
+# Include some module-level tests
+h = lastchar("hello")
+assert(h == "o")
+assert(lastchar("hello") == "o")
+
+test()
\ No newline at end of file
diff --git a/tests/tests.bish b/tests/tests.bish
index 5e61a8e..360cedf 100644
--- a/tests/tests.bish
+++ b/tests/tests.bish
@@ -46,6 +46,9 @@ def run_all() {
 
     import return_vals
     return_vals.test()
+
+    import conditionals
+    conditionals.test()
 }
 
 change_dir()