Move //cargo specific tests to //cargo/tests (#3874)

This also includes minor updates to account for the new placement of
data files.

Author: UebelAndre

test/cargo_build_script/BUILD.bazel cargo/tests/BUILD.bazeltest/cargo_build_script/BUILD.bazel renamed to cargo/tests/BUILD.bazel

@@ -0,0 +1,24 @@
+load("//cargo:defs.bzl", "cargo_build_script")
+load("//rust:rust_test.bzl", "rust_test")
+
+rust_test(
+    # Intentionally uses a mix of -s and _s because those normalisations are part of what is being tested.
+    name = "cargo_env-vars_test",
+    srcs = ["tests/cargo.rs"],
+    edition = "2018",
+    deps = [":cargo_build_script_env-vars_bs"],
+)
+
+rust_test(
+    name = "cargo-env-vars-custom-crate-name-test",
+    srcs = ["tests/custom_crate_name.rs"],
+    crate_name = "custom_crate_name",
+    edition = "2018",
+    deps = [":cargo_build_script_env-vars_bs"],
+)
+
+cargo_build_script(
+    name = "cargo_build_script_env-vars_bs",
+    srcs = ["src/build.rs"],
+    edition = "2018",
+)

cargo/tests/build_env/BUILD.bazel

@@ -0,0 +1 @@
+This file tests that CARGO_MANIFEST_DIR is set for the build environment

test/build_env/src/build.rs cargo/tests/build_env/src/build.rstest/build_env/src/build.rs renamed to cargo/tests/build_env/src/build.rs

@@ -0,0 +1,8 @@
+#[test]
+fn cargo_env_vars() {
+    assert_eq!(
+        env!("CARGO_PKG_NAME"),
+        "cargo-env-vars-custom-crate-name-test"
+    );
+    assert_eq!(env!("CARGO_CRATE_NAME"), "custom_crate_name");
+}

cargo/tests/build_env/src/manifest_dir_file.txt

@@ -0,0 +1,10 @@
+#[test]
+pub fn test_manifest_dir() {
+    let actual = include_str!(concat!(
+        env!("CARGO_MANIFEST_DIR"),
+        "/src/manifest_dir_file.txt"
+    ))
+    .trim_end();
+    let expected = "This file tests that CARGO_MANIFEST_DIR is set for the build environment";
+    assert_eq!(actual, expected);
+}