diff --git a/testdata/foldl_empty.golden b/testdata/foldl_empty.golden
new file mode 100644
index 0000000..19765bd
--- /dev/null
+++ b/testdata/foldl_empty.golden
@@ -0,0 +1 @@
+null
diff --git a/testdata/foldl_empty.jsonnet b/testdata/foldl_empty.jsonnet
new file mode 100644
index 0000000..5724848
--- /dev/null
+++ b/testdata/foldl_empty.jsonnet
@@ -0,0 +1 @@
+std.foldl(function(i, v) i + v, [], null)
diff --git a/testdata/foldl_empty.linter.golden b/testdata/foldl_empty.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldl_single_element.golden b/testdata/foldl_single_element.golden
new file mode 100644
index 0000000..cb5537d
--- /dev/null
+++ b/testdata/foldl_single_element.golden
@@ -0,0 +1 @@
+"ab"
diff --git a/testdata/foldl_single_element.jsonnet b/testdata/foldl_single_element.jsonnet
new file mode 100644
index 0000000..1308f69
--- /dev/null
+++ b/testdata/foldl_single_element.jsonnet
@@ -0,0 +1 @@
+std.foldl(function(i, v) i + v, 'b', 'a')
diff --git a/testdata/foldl_single_element.linter.golden b/testdata/foldl_single_element.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldl_string.golden b/testdata/foldl_string.golden
new file mode 100644
index 0000000..86ba662
--- /dev/null
+++ b/testdata/foldl_string.golden
@@ -0,0 +1 @@
+"abbccdd"
diff --git a/testdata/foldl_string.jsonnet b/testdata/foldl_string.jsonnet
new file mode 100644
index 0000000..4b81d2b
--- /dev/null
+++ b/testdata/foldl_string.jsonnet
@@ -0,0 +1 @@
+std.foldl(function(i, v) i + v + v, 'bcd', 'a')
diff --git a/testdata/foldl_string.linter.golden b/testdata/foldl_string.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldl_various.golden b/testdata/foldl_various.golden
new file mode 100644
index 0000000..2ebfea5
--- /dev/null
+++ b/testdata/foldl_various.golden
@@ -0,0 +1 @@
+"a2[1, 2, 3]{\"foo\": \"bar\"}"
diff --git a/testdata/foldl_various.jsonnet b/testdata/foldl_various.jsonnet
new file mode 100644
index 0000000..097fd23
--- /dev/null
+++ b/testdata/foldl_various.jsonnet
@@ -0,0 +1 @@
+std.foldl(function(i, v) i + std.toString(v), ['a', 2, [1, 2, 3], { foo: 'bar' }], '')
diff --git a/testdata/foldl_various.linter.golden b/testdata/foldl_various.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldr_empty.golden b/testdata/foldr_empty.golden
new file mode 100644
index 0000000..19765bd
--- /dev/null
+++ b/testdata/foldr_empty.golden
@@ -0,0 +1 @@
+null
diff --git a/testdata/foldr_empty.jsonnet b/testdata/foldr_empty.jsonnet
new file mode 100644
index 0000000..f3592f5
--- /dev/null
+++ b/testdata/foldr_empty.jsonnet
@@ -0,0 +1 @@
+std.foldr(function(i, v) i + v, [], null)
diff --git a/testdata/foldr_empty.linter.golden b/testdata/foldr_empty.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldr_single_element.golden b/testdata/foldr_single_element.golden
new file mode 100644
index 0000000..cb5537d
--- /dev/null
+++ b/testdata/foldr_single_element.golden
@@ -0,0 +1 @@
+"ab"
diff --git a/testdata/foldr_single_element.jsonnet b/testdata/foldr_single_element.jsonnet
new file mode 100644
index 0000000..fd6d884
--- /dev/null
+++ b/testdata/foldr_single_element.jsonnet
@@ -0,0 +1 @@
+std.foldr(function(v, i) i + v, 'b', 'a')
diff --git a/testdata/foldr_single_element.linter.golden b/testdata/foldr_single_element.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldr_string.golden b/testdata/foldr_string.golden
new file mode 100644
index 0000000..c23c5f4
--- /dev/null
+++ b/testdata/foldr_string.golden
@@ -0,0 +1 @@
+"addccbb"
diff --git a/testdata/foldr_string.jsonnet b/testdata/foldr_string.jsonnet
new file mode 100644
index 0000000..d8bfa21
--- /dev/null
+++ b/testdata/foldr_string.jsonnet
@@ -0,0 +1 @@
+std.foldr(function(v, i) i + v + v, 'bcd', 'a')
diff --git a/testdata/foldr_string.linter.golden b/testdata/foldr_string.linter.golden
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/foldr_various.golden b/testdata/foldr_various.golden
new file mode 100644
index 0000000..fb36f19
--- /dev/null
+++ b/testdata/foldr_various.golden
@@ -0,0 +1 @@
+"{\"foo\": \"bar\"}[1, 2, 3]2a"
diff --git a/testdata/foldr_various.jsonnet b/testdata/foldr_various.jsonnet
new file mode 100644
index 0000000..375eb6a
--- /dev/null
+++ b/testdata/foldr_various.jsonnet
@@ -0,0 +1 @@
+std.foldr(function(v, i) i + std.toString(v), ['a', 2, [1, 2, 3], { foo: 'bar' }], '')
diff --git a/testdata/foldr_various.linter.golden b/testdata/foldr_various.linter.golden
new file mode 100644
index 0000000..e69de29