diff --git a/crates/cli/tests/cli_run.rs b/crates/cli/tests/cli_run.rs
index f3e97456c0..cb54b40323 100644
--- a/crates/cli/tests/cli_run.rs
+++ b/crates/cli/tests/cli_run.rs
@@ -353,10 +353,10 @@ mod cli_run {
 
         if use_valgrind.and_is_supported() {
             let out = runner.run_with_valgrind();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -382,11 +382,11 @@ mod cli_run {
         if use_valgrind.and_is_supported() {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -394,7 +394,7 @@ mod cli_run {
     #[serial(zig_platform_parser_package_basic_cli_url)]
     #[cfg_attr(windows, ignore)]
     fn hello_world() {
-        let expected_ending = "Hello, World!\n";
+        let expected_ending = "Hello, World!\n🔨 Building host ...\n";
         let runner = Run::new_roc()
             .arg(CMD_RUN)
             .arg(BUILD_HOST_FLAG)
@@ -404,11 +404,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -431,11 +431,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -456,11 +456,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -479,11 +479,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -499,102 +499,6 @@ mod cli_run {
         out.assert_clean_success();
     }
 
-    #[ignore = "TODO move this to roc-lang/examples repository"]
-    #[test]
-    fn expects_dev_and_test() {
-        // these are in the same test function so we don't have to worry about race conditions
-        // on the building of the platform
-
-        test_roc_app(
-            from_root("crates/cli/tests/expects", "expects.roc").as_path(),
-            vec![],
-            &[],
-            vec![],
-            indoc!(
-                r#"
-                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
-
-                This expectation failed:
-
-                28│      expect words == []
-                                ^^^^^^^^^^^
-
-                When it failed, these variables had these values:
-
-                words : List Str
-                words = ["this", "will", "for", "sure", "be", "a", "large", "string", "so", "when", "we", "split", "it", "it", "will", "use", "seamless", "slices", "which", "affect", "printing"]
-
-                [<ignored for tests>:31] x = 42
-                [<ignored for tests>:33] "Fjoer en ferdjer frieten oan dyn geve lea" = "Fjoer en ferdjer frieten oan dyn geve lea"
-                [<ignored for tests>:35] "this is line 24" = "this is line 24"
-                [<ignored for tests>:21] x = "abc"
-                [<ignored for tests>:21] x = 10
-                [<ignored for tests>:21] x = (A (B C))
-                Program finished!
-                "#
-            ),
-            UseValgrind::Yes,
-            TestCliCommands::Dev,
-        );
-
-        test_roc_app(
-            from_root("crates/cli/tests/expects", "expects.roc").as_path(),
-            vec![],
-            &[],
-            vec![],
-            indoc!(
-                r#"
-                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
-
-                This expectation failed:
-
-                9│      expect a == 2
-                               ^^^^^^
-
-                When it failed, these variables had these values:
-
-                a : Num *
-                a = 1
-
-                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
-
-                This expectation failed:
-
-                10│      expect a == 3
-                                ^^^^^^
-
-                When it failed, these variables had these values:
-
-                a : Num *
-                a = 1
-
-                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
-
-                This expectation failed:
-
-                14│>  expect
-                15│>      a = makeA
-                16│>      b = 2i64
-                17│>
-                18│>      a == b
-
-                When it failed, these variables had these values:
-
-                a : Int Signed64
-                a = 1
-
-                b : I64
-                b = 2
-
-
-                1 failed and 0 passed in <ignored for test> ms.
-                "#
-            ),
-            UseValgrind::Yes,
-            TestCliCommands::Test,
-        );
-    }
-
     #[test]
     #[cfg_attr(windows, ignore)]
     fn test_module_imports_pkg_w_flag() {
@@ -610,10 +514,10 @@ mod cli_run {
 
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -643,10 +547,10 @@ mod cli_run {
 
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -686,10 +590,10 @@ mod cli_run {
 
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -706,7 +610,7 @@ mod cli_run {
 
         let out = runner.run();
         out.assert_clean_success();
-        out.assert_stdout_ends_with(expected_ending);
+        out.assert_stdout_and_stderr_ends_with(expected_ending);
     }
 
     #[test]
@@ -723,10 +627,10 @@ mod cli_run {
 
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -751,10 +655,10 @@ mod cli_run {
 
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -774,11 +678,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -796,11 +700,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -1074,7 +978,7 @@ mod cli_run {
 
         let out = runner.run();
         out.assert_clean_success();
-        out.assert_stdout_ends_with(expected_ending);
+        out.assert_stdout_and_stderr_ends_with(expected_ending);
     }
 
     #[test]
@@ -1090,7 +994,7 @@ mod cli_run {
 
         let out = runner.run();
         out.assert_clean_success();
-        out.assert_stdout_ends_with(expected_ending);
+        out.assert_stdout_and_stderr_ends_with(expected_ending);
     }
 
     #[test]
@@ -1107,11 +1011,11 @@ mod cli_run {
         if ALLOW_VALGRIND {
             let out = runner.run_with_valgrind();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         } else {
             let out = runner.run();
             out.assert_clean_success();
-            out.assert_stdout_ends_with(expected_ending);
+            out.assert_stdout_and_stderr_ends_with(expected_ending);
         }
     }
 
@@ -1120,7 +1024,8 @@ mod cli_run {
             ALLOW_VALGRIND, BUILD_HOST_FLAG, OPTIMIZE_FLAG, SUPPRESS_BUILD_HOST_WARNING_FLAG,
         };
         use cli_utils::helpers::{from_root, Run};
-        use roc_cli::{CMD_BUILD, CMD_RUN};
+        use indoc::indoc;
+        use roc_cli::{CMD_BUILD, CMD_DEV, CMD_RUN, CMD_TEST};
 
         static BUILD_PLATFORM_HOST: std::sync::Once = std::sync::Once::new();
 
@@ -1136,7 +1041,6 @@ mod cli_run {
                         from_root("crates/cli/tests/test-platform-simple-zig", "app.roc").as_path(),
                     )
                     .run();
-                dbg!(&out);
                 out.assert_clean_success();
             });
         }
@@ -1154,11 +1058,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1176,11 +1080,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1197,11 +1101,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1222,11 +1126,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1244,11 +1148,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1267,11 +1171,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1293,11 +1197,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1319,11 +1223,11 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
 
@@ -1345,11 +1249,123 @@ mod cli_run {
             if ALLOW_VALGRIND {
                 let out = runner.run_with_valgrind();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             } else {
                 let out = runner.run();
                 out.assert_clean_success();
-                out.assert_stdout_ends_with(expected_ending);
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
+            }
+        }
+
+        #[test]
+        fn expects_dev() {
+            build_platform_host();
+
+            let expected_ending = indoc!(
+                r#"
+                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
+
+                This expectation failed:
+
+                25│      expect words == []
+                                ^^^^^^^^^^^
+
+                When it failed, these variables had these values:
+
+                words : List Str
+                words = ["this", "will", "for", "sure", "be", "a", "large", "string", "so", "when", "we", "split", "it", "it", "will", "use", "seamless", "slices", "which", "affect", "printing"]
+
+                Program finished!
+
+                [<ignored for tests>:28] x = 42
+                [<ignored for tests>:30] "Fjoer en ferdjer frieten oan dyn geve lea" = "Fjoer en ferdjer frieten oan dyn geve lea"
+                [<ignored for tests>:32] "this is line 24" = "this is line 24"
+                [<ignored for tests>:18] x = "abc"
+                [<ignored for tests>:18] x = 10
+                [<ignored for tests>:18] x = (A (B C))
+                "#
+            );
+            let runner = cli_utils::helpers::Run::new_roc()
+                .arg(CMD_DEV)
+                .arg(from_root("crates/cli/tests/expects", "expects.roc").as_path());
+
+            dbg!(&runner);
+
+            if ALLOW_VALGRIND {
+                let out = runner.run_with_valgrind();
+                // out.assert_clean_success();
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
+            } else {
+                let out = runner.run();
+                // out.assert_clean_success();
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
+            }
+        }
+
+        #[test]
+        fn expects_test() {
+            build_platform_host();
+
+            let expected_ending = indoc!(
+                r#"
+                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
+
+                This expectation failed:
+
+                9│      expect a == 2
+                               ^^^^^^
+
+                When it failed, these variables had these values:
+
+                a : Num *
+                a = 1
+
+                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
+
+                This expectation failed:
+
+                10│      expect a == 3
+                                ^^^^^^
+
+                When it failed, these variables had these values:
+
+                a : Num *
+                a = 1
+
+                ── EXPECT FAILED in tests/expects/expects.roc ──────────────────────────────────
+
+                This expectation failed:
+
+                14│>  expect
+                15│>      a = makeA
+                16│>      b = 2i64
+                17│>
+                18│>      a == b
+
+                When it failed, these variables had these values:
+
+                a : Int Signed64
+                a = 1
+
+                b : I64
+                b = 2
+
+
+                1 failed and 0 passed in <ignored for test> ms.
+                "#
+            );
+            let runner = cli_utils::helpers::Run::new_roc()
+                .arg(CMD_TEST)
+                .arg(from_root("crates/cli/tests/expects", "expects.roc").as_path());
+
+            if ALLOW_VALGRIND {
+                let out = runner.run_with_valgrind();
+                out.assert_clean_success();
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
+            } else {
+                let out = runner.run();
+                out.assert_clean_success();
+                out.assert_stdout_and_stderr_ends_with(expected_ending);
             }
         }
     }
@@ -1391,11 +1407,11 @@ mod cli_run {
                 if use_valgrind.and_is_supported() {
                     let out = runner.run_with_valgrind();
                     out.assert_clean_success();
-                    out.assert_stdout_ends_with(expected_ending);
+                    out.assert_stdout_and_stderr_ends_with(expected_ending);
                 } else {
                     let out = runner.run();
                     out.assert_clean_success();
-                    out.assert_stdout_ends_with(expected_ending);
+                    out.assert_stdout_and_stderr_ends_with(expected_ending);
                 }
             }
 
@@ -1633,9 +1649,9 @@ mod cli_run {
 
                 Something is off with the body of the main definition:
 
-                6│  main : Str -> Task {} []
-                7│  main = /_ ->
-                8│      "this is a string, not a Task {} [] function like the platform expects."
+                5│  main : Str -> Task {} []
+                6│  main = /_ ->
+                7│      "this is a string, not a Task {} [] function like the platform expects."
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
                 The body is a string of type:
@@ -1667,8 +1683,8 @@ mod cli_run {
 
                 Symbol is imported but not used.
 
-                3│      imports [Symbol.{ Ident }]
-                                 ^^^^^^^^^^^^^^^^
+                3│  import Symbol exposing [Ident]
+                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
                 Since Symbol isn't used, you don't need to import it.
 
@@ -1711,8 +1727,8 @@ mod cli_run {
 
                 Symbol is imported but not used.
 
-                3│      imports [Symbol.{ Ident }]
-                                 ^^^^^^^^^^^^^^^^
+                3│  import Symbol exposing [Ident]
+                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
                 Since Symbol isn't used, you don't need to import it.
 
diff --git a/crates/cli/tests/expects/expects.roc b/crates/cli/tests/expects/expects.roc
index e2125c0d99..439fcf250f 100644
--- a/crates/cli/tests/expects/expects.roc
+++ b/crates/cli/tests/expects/expects.roc
@@ -1,7 +1,4 @@
-app "expects-test"
-    packages { pf: "zig-platform/main.roc" }
-    imports []
-    provides [main] to pf
+app [main] { pf: platform "../test-platform-simple-zig/main.roc" }
 
 makeA =
     a = 1
diff --git a/crates/cli/tests/expects/zig-platform/host.zig b/crates/cli/tests/expects/zig-platform/host.zig
deleted file mode 100644
index 1ac9ce6dbe..0000000000
--- a/crates/cli/tests/expects/zig-platform/host.zig
+++ /dev/null
@@ -1,129 +0,0 @@
-const std = @import("std");
-const builtin = @import("builtin");
-const str = @import("glue").str;
-const RocStr = str.RocStr;
-const testing = std.testing;
-const expectEqual = testing.expectEqual;
-const expect = testing.expect;
-
-const Align = 2 * @alignOf(usize);
-extern fn malloc(size: usize) callconv(.C) ?*align(Align) anyopaque;
-extern fn realloc(c_ptr: [*]align(Align) u8, size: usize) callconv(.C) ?*anyopaque;
-extern fn free(c_ptr: [*]align(Align) u8) callconv(.C) void;
-extern fn memcpy(dst: [*]u8, src: [*]u8, size: usize) callconv(.C) void;
-extern fn memset(dst: [*]u8, value: i32, size: usize) callconv(.C) void;
-
-const DEBUG: bool = false;
-
-export fn roc_alloc(size: usize, alignment: u32) callconv(.C) ?*anyopaque {
-    if (DEBUG) {
-        var ptr = malloc(size);
-        const stdout = std.io.getStdOut().writer();
-        stdout.print("alloc:   {d} (alignment {d}, size {d})\n", .{ ptr, alignment, size }) catch unreachable;
-        return ptr;
-    } else {
-        return malloc(size);
-    }
-}
-
-export fn roc_realloc(c_ptr: *anyopaque, new_size: usize, old_size: usize, alignment: u32) callconv(.C) ?*anyopaque {
-    if (DEBUG) {
-        const stdout = std.io.getStdOut().writer();
-        stdout.print("realloc: {d} (alignment {d}, old_size {d})\n", .{ c_ptr, alignment, old_size }) catch unreachable;
-    }
-
-    return realloc(@as([*]align(Align) u8, @alignCast(@ptrCast(c_ptr))), new_size);
-}
-
-export fn roc_dealloc(c_ptr: *anyopaque, alignment: u32) callconv(.C) void {
-    if (DEBUG) {
-        const stdout = std.io.getStdOut().writer();
-        stdout.print("dealloc: {d} (alignment {d})\n", .{ c_ptr, alignment }) catch unreachable;
-    }
-
-    free(@as([*]align(Align) u8, @alignCast(@ptrCast(c_ptr))));
-}
-
-export fn roc_panic(msg: *RocStr, tag_id: u32) callconv(.C) void {
-    _ = tag_id;
-
-    const stderr = std.io.getStdErr().writer();
-    stderr.print("Application crashed with message\n\n    {s}\n\nShutting down\n", .{msg.asSlice()}) catch unreachable;
-    std.process.exit(1);
-}
-
-export fn roc_dbg(loc: *RocStr, msg: *RocStr, src: *RocStr) callconv(.C) void {
-    // This platform uses stdout for testing purposes instead of the normal stderr.
-    const stdout = std.io.getStdOut().writer();
-    stdout.print("[{s}] {s} = {s}\n", .{ loc.asSlice(), src.asSlice(), msg.asSlice() }) catch unreachable;
-}
-
-export fn roc_memset(dst: [*]u8, value: i32, size: usize) callconv(.C) void {
-    return memset(dst, value, size);
-}
-
-extern fn kill(pid: c_int, sig: c_int) c_int;
-extern fn shm_open(name: *const i8, oflag: c_int, mode: c_uint) c_int;
-extern fn mmap(addr: ?*anyopaque, length: c_uint, prot: c_int, flags: c_int, fd: c_int, offset: c_uint) *anyopaque;
-extern fn getppid() c_int;
-
-fn roc_getppid() callconv(.C) c_int {
-    return getppid();
-}
-
-fn roc_getppid_windows_stub() callconv(.C) c_int {
-    return 0;
-}
-
-fn roc_send_signal(pid: c_int, sig: c_int) callconv(.C) c_int {
-    return kill(pid, sig);
-}
-fn roc_shm_open(name: *const i8, oflag: c_int, mode: c_uint) callconv(.C) c_int {
-    return shm_open(name, oflag, mode);
-}
-fn roc_mmap(addr: ?*anyopaque, length: c_uint, prot: c_int, flags: c_int, fd: c_int, offset: c_uint) callconv(.C) *anyopaque {
-    return mmap(addr, length, prot, flags, fd, offset);
-}
-
-comptime {
-    if (builtin.os.tag == .macos or builtin.os.tag == .linux) {
-        @export(roc_getppid, .{ .name = "roc_getppid", .linkage = .Strong });
-        @export(roc_mmap, .{ .name = "roc_mmap", .linkage = .Strong });
-        @export(roc_send_signal, .{ .name = "roc_send_signal", .linkage = .Strong });
-        @export(roc_shm_open, .{ .name = "roc_shm_open", .linkage = .Strong });
-    }
-
-    if (builtin.os.tag == .windows) {
-        @export(roc_getppid_windows_stub, .{ .name = "roc_getppid", .linkage = .Strong });
-    }
-}
-
-const mem = std.mem;
-const Allocator = mem.Allocator;
-
-extern fn roc__mainForHost_1_exposed_generic(*RocStr) void;
-
-const Unit = extern struct {};
-
-pub fn main() u8 {
-    const stdout = std.io.getStdOut().writer();
-    const stderr = std.io.getStdErr().writer();
-
-    var timer = std.time.Timer.start() catch unreachable;
-
-    // actually call roc to populate the callresult
-    var callresult = RocStr.empty();
-    roc__mainForHost_1_exposed_generic(&callresult);
-
-    const nanos = timer.read();
-    const seconds = (@as(f64, @floatFromInt(nanos)) / 1_000_000_000.0);
-
-    // stdout the result
-    stdout.print("{s}", .{callresult.asSlice()}) catch unreachable;
-
-    callresult.decref();
-
-    stderr.print("runtime: {d:.3}ms\n", .{seconds * 1000}) catch unreachable;
-
-    return 0;
-}
diff --git a/crates/cli/tests/expects/zig-platform/main.roc b/crates/cli/tests/expects/zig-platform/main.roc
deleted file mode 100644
index a52fe9a480..0000000000
--- a/crates/cli/tests/expects/zig-platform/main.roc
+++ /dev/null
@@ -1,9 +0,0 @@
-platform "echo-in-zig"
-    requires {} { main : Str }
-    exposes []
-    packages {}
-    imports []
-    provides [mainForHost]
-
-mainForHost : Str
-mainForHost = main
diff --git a/crates/cli/tests/test-platform-simple-zig/host.zig b/crates/cli/tests/test-platform-simple-zig/host.zig
index 029a3ea4ed..707bfeb4b2 100644
--- a/crates/cli/tests/test-platform-simple-zig/host.zig
+++ b/crates/cli/tests/test-platform-simple-zig/host.zig
@@ -93,27 +93,15 @@ const Unit = extern struct {};
 
 pub export fn main() i32 {
     const stdout = std.io.getStdOut().writer();
-    const stderr = std.io.getStdErr().writer();
-
-    var timer = std.time.Timer.start() catch unreachable;
 
     // actually call roc to populate the callresult
     var callresult = RocStr.empty();
     roc__mainForHost_1_exposed_generic(&callresult);
 
-    const nanos = timer.read();
-    const seconds = (@as(f64, @floatFromInt(nanos)) / 1_000_000_000.0);
-
     // stdout the result
     stdout.print("{s}\n", .{callresult.asSlice()}) catch unreachable;
 
     callresult.decref();
 
-    stderr.print("runtime: {d:.3}ms\n", .{seconds * 1000}) catch unreachable;
-
     return 0;
 }
-
-fn to_seconds(tms: std.os.timespec) f64 {
-    return @as(f64, @floatFromInt(tms.tv_sec)) + (@as(f64, @floatFromInt(tms.tv_nsec)) / 1_000_000_000.0);
-}
diff --git a/crates/cli_utils/src/helpers.rs b/crates/cli_utils/src/helpers.rs
index e21c5a2c8d..633011ec94 100644
--- a/crates/cli_utils/src/helpers.rs
+++ b/crates/cli_utils/src/helpers.rs
@@ -6,6 +6,7 @@ extern crate tempfile;
 
 use regex::Regex;
 use roc_command_utils::{cargo, pretty_command_string, root_dir};
+use roc_reporting::report::ANSI_STYLE_CODES;
 use serde::Deserialize;
 use serde_xml_rs::from_str;
 use std::env;
@@ -56,10 +57,13 @@ impl std::fmt::Display for Out {
 }
 
 impl Out {
+    /// Assert that the command succeeded and that there are no unexpected errors in the stderr.
     pub fn assert_clean_success(&self) {
         self.assert_success_with_no_unexpected_errors(COMMON_STDERR.as_slice());
     }
 
+    /// Assert that the command succeeded and that there are no unexpected errors in the stderr.
+    /// This DOES NOT normalise the output, use assert_stdout_ends_with for that.
     pub fn assert_success_with_no_unexpected_errors(&self, expected_errors: &[ExpectedString]) {
         assert!(self.status.success(), "Command failed\n\n{self}");
         assert!(
@@ -69,23 +73,47 @@ impl Out {
         );
     }
 
-    /// Normalise the output for comparison in tests by stripping ANSI color codes
-    /// and replace test timings with a placeholder.
-    pub fn stdout_without_test_timings(&self) -> String {
+    /// Normalise the output for comparison in tests by replacing with a placeholder
+    fn normalize_for_tests(input: &String) -> String {
+        // remove ANSI color codes
         let ansi_regex = Regex::new(r"\x1b\[[0-9;]*[mGKH]").expect("Invalid ANSI regex pattern");
-        let without_ansi = ansi_regex.replace_all(&self.stdout, "");
+        let without_ansi = ansi_regex.replace_all(input, "");
 
+        // replace timings with a placeholder
         let regex = Regex::new(r" in (\d+) ms\.").expect("Invalid regex pattern");
         let replacement = " in <ignored for test> ms.";
-        regex.replace_all(&without_ansi, replacement).to_string()
+        let without_timings = regex.replace_all(&without_ansi, replacement);
+
+        // replace file paths with a placeholder
+        let filepath_regex =
+            Regex::new(r"\[([^:]+):(\d+)\]").expect("Invalid filepath regex pattern");
+        let filepath_replacement = "[<ignored for tests>:$2]";
+        filepath_regex
+            .replace_all(&without_timings, filepath_replacement)
+            .to_string()
     }
 
-    pub fn assert_stdout_ends_with(&self, expected: &str) {
+    /// Assert that the stdout ends with the expected string
+    /// This normalises the output for comparison in tests such as replacing timings
+    /// with a placeholder, or stripping ANSI colors
+    pub fn assert_stdout_and_stderr_ends_with(&self, expected: &str) {
+        let normalised_output = format!(
+            "{}{}",
+            Out::normalize_for_tests(&self.stdout),
+            Out::normalize_for_tests(&self.stderr)
+        );
+
         assert!(
-            dbg!(self.stdout_without_test_timings()).ends_with(expected),
-            "Expected stdout to end with:\n{}\n\nActual stdout:\n{}",
+            normalised_output.ends_with(expected),
+            "\n{}EXPECTED stdout and stderr after normalizing:\n----------------\n{}{}\n{}ACTUAL stdout and stderr after normalizing:\n----------------\n{}{}{}\n----------------\n{}",
+            ANSI_STYLE_CODES.cyan,
+            ANSI_STYLE_CODES.reset,
             expected,
-            self.stdout
+            ANSI_STYLE_CODES.cyan,
+            ANSI_STYLE_CODES.reset,
+            normalised_output,
+            ANSI_STYLE_CODES.cyan,
+            ANSI_STYLE_CODES.reset,
         );
     }
 }