Clean up imports, formatting and tests.

Bug: n/a
Test: atest libapkverify.test libapkverify.integration_test
Change-Id: I39686d17927741297aa3feb02ed6043ee770933b
diff --git a/apkverify/src/bytes_ext.rs b/apkverify/src/bytes_ext.rs
index 1b8d6b6..22a3085 100644
--- a/apkverify/src/bytes_ext.rs
+++ b/apkverify/src/bytes_ext.rs
@@ -98,7 +98,9 @@
 
 #[cfg(test)]
 mod tests {
+    use super::*;
     use bytes::{BufMut, BytesMut};
+
     #[test]
     fn test_read_length_prefixed_slice() {
         let data = b"hello world";
@@ -106,7 +108,7 @@
         b.put_u32_le(data.len() as u32);
         b.put_slice(data);
         let mut slice = b.freeze();
-        let res = super::read_length_prefixed_slice(&mut slice);
+        let res = read_length_prefixed_slice(&mut slice);
         assert!(res.is_ok());
         assert_eq!(data, res.ok().unwrap().as_ref());
     }
diff --git a/apkverify/src/lib.rs b/apkverify/src/lib.rs
index 869431e..f75913c 100644
--- a/apkverify/src/lib.rs
+++ b/apkverify/src/lib.rs
@@ -18,7 +18,8 @@
 
 mod bytes_ext;
 mod sigutil;
-mod testing;
+#[allow(dead_code)]
+pub mod testing;
 mod v3;
 mod ziputil;
 
diff --git a/apkverify/src/sigutil.rs b/apkverify/src/sigutil.rs
index 06645fe..fc92898 100644
--- a/apkverify/src/sigutil.rs
+++ b/apkverify/src/sigutil.rs
@@ -18,7 +18,7 @@
 
 use anyhow::{anyhow, bail, Result};
 use byteorder::{LittleEndian, ReadBytesExt};
-use bytes::{Buf, BufMut, Bytes};
+use bytes::{Buf, BufMut, Bytes, BytesMut};
 use ring::digest;
 use std::cmp::min;
 use std::io::{Cursor, Read, Seek, SeekFrom, Take};
@@ -61,11 +61,11 @@
 
 impl<R: Read + Seek> ApkSections<R> {
     pub fn new(reader: R) -> Result<ApkSections<R>> {
-        let (mut f, zip_sections) = zip_sections(reader)?;
+        let (mut reader, zip_sections) = zip_sections(reader)?;
         let (signing_block_offset, signing_block_size) =
-            find_signing_block(&mut f, zip_sections.central_directory_offset)?;
+            find_signing_block(&mut reader, zip_sections.central_directory_offset)?;
         Ok(ApkSections {
-            inner: f,
+            inner: reader,
             signing_block_offset,
             signing_block_size,
             central_directory_offset: zip_sections.central_directory_offset,
@@ -93,7 +93,7 @@
     pub fn compute_digest(&mut self, signature_algorithm_id: u32) -> Result<Vec<u8>> {
         let digester = Digester::new(signature_algorithm_id)?;
 
-        let mut digests_of_chunks = bytes::BytesMut::new();
+        let mut digests_of_chunks = BytesMut::new();
         let mut chunk_count = 0u32;
         let mut chunk = vec![0u8; CHUNK_SIZE_BYTES as usize];
         for data in &[
@@ -118,6 +118,7 @@
     fn zip_entries(&mut self) -> Result<Take<Box<dyn Read + '_>>> {
         scoped_read(&mut self.inner, 0, self.signing_block_offset as u64)
     }
+
     fn central_directory(&mut self) -> Result<Take<Box<dyn Read + '_>>> {
         scoped_read(
             &mut self.inner,
@@ -125,6 +126,7 @@
             self.central_directory_size as u64,
         )
     }
+
     fn eocd_for_verification(&mut self) -> Result<Take<Box<dyn Read + '_>>> {
         let mut eocd = self.bytes(self.eocd_offset, self.eocd_size)?;
         // Protection of section 4 (ZIP End of Central Directory) is complicated by the section
@@ -136,6 +138,7 @@
         set_central_directory_offset(&mut eocd, self.signing_block_offset)?;
         Ok(Read::take(Box::new(Cursor::new(eocd)), self.eocd_size as u64))
     }
+
     fn bytes(&mut self, offset: u32, size: u32) -> Result<Vec<u8>> {
         self.inner.seek(SeekFrom::Start(offset as u64))?;
         let mut buf = vec![0u8; size as usize];
@@ -159,6 +162,7 @@
 
 const CHUNK_HEADER_TOP: &[u8] = &[0x5a];
 const CHUNK_HEADER_MID: &[u8] = &[0xa5];
+
 impl Digester {
     fn new(signature_algorithm_id: u32) -> Result<Digester> {
         let digest_algorithm_id = to_content_digest_algorithm(signature_algorithm_id)?;
@@ -173,6 +177,7 @@
         };
         Ok(Digester { algorithm })
     }
+
     // v2/v3 digests are computed after prepending "header" byte and "size" info.
     fn digest(&self, data: &[u8], header: &[u8], size: u32) -> digest::Digest {
         let mut ctx = digest::Context::new(self.algorithm);
diff --git a/apkverify/src/testing.rs b/apkverify/src/testing.rs
index 777afb8..301a9c3 100644
--- a/apkverify/src/testing.rs
+++ b/apkverify/src/testing.rs
@@ -16,19 +16,7 @@
 
 //! A collection of utilities for testing
 
-/// Asserts if `haystack.contains(needed)`
-#[macro_export]
-macro_rules! assert_contains {
-    ($haystack:expr,$needle:expr $(,)?) => {
-        match (&$haystack, &$needle) {
-            (haystack_value, needle_value) => {
-                assert!(
-                    haystack_value.contains(needle_value),
-                    "{} is not found in {}",
-                    needle_value,
-                    haystack_value
-                );
-            }
-        }
-    };
+/// Asserts if `haystack.contains(needle)`
+pub fn assert_contains(haystack: &str, needle: &str) {
+    assert!(haystack.contains(needle), "{} is not found in {}", needle, haystack);
 }
diff --git a/apkverify/src/v3.rs b/apkverify/src/v3.rs
index d1f59c6..2f9ce94 100644
--- a/apkverify/src/v3.rs
+++ b/apkverify/src/v3.rs
@@ -21,11 +21,15 @@
 
 use anyhow::{anyhow, bail, Context, Result};
 use bytes::Bytes;
+use ring::signature::{
+    UnparsedPublicKey, VerificationAlgorithm, ECDSA_P256_SHA256_ASN1, RSA_PKCS1_2048_8192_SHA256,
+    RSA_PKCS1_2048_8192_SHA512, RSA_PSS_2048_8192_SHA256, RSA_PSS_2048_8192_SHA512,
+};
 use std::fs::File;
 use std::io::{Read, Seek};
 use std::ops::Range;
 use std::path::Path;
-use x509_parser::{prelude::FromDer, x509};
+use x509_parser::{parse_x509_certificate, prelude::FromDer, x509::SubjectPublicKeyInfo};
 
 use crate::bytes_ext::{BytesExt, LengthPrefixed, ReadFromBytes};
 use crate::sigutil::*;
@@ -45,7 +49,7 @@
     min_sdk: u32,
     max_sdk: u32,
     signatures: LengthPrefixed<Vec<LengthPrefixed<Signature>>>,
-    public_key: LengthPrefixed<SubjectPublicKeyInfo>,
+    public_key: LengthPrefixed<Bytes>,
 }
 
 impl Signer {
@@ -79,7 +83,6 @@
     digest: LengthPrefixed<Bytes>,
 }
 
-type SubjectPublicKeyInfo = Bytes;
 type X509Certificate = Bytes;
 type AdditionalAttributes = Bytes;
 
@@ -128,7 +131,7 @@
 
         // 2. Verify the corresponding signature from signatures against signed data using public key.
         //    (It is now safe to parse signed data.)
-        let (_, key_info) = x509::SubjectPublicKeyInfo::from_der(self.public_key.as_ref())?;
+        let (_, key_info) = SubjectPublicKeyInfo::from_der(self.public_key.as_ref())?;
         verify_signed_data(&self.signed_data, strongest, &key_info)?;
 
         // It is now safe to parse signed data.
@@ -172,7 +175,7 @@
         // 7. Verify that SubjectPublicKeyInfo of the first certificate of certificates is identical
         //    to public key.
         let cert = signed_data.certificates.first().context("No certificates listed")?;
-        let (_, cert) = x509_parser::parse_x509_certificate(cert.as_ref())?;
+        let (_, cert) = parse_x509_certificate(cert.as_ref())?;
         if cert.tbs_certificate.subject_pki != key_info {
             bail!("Public key mismatch between certificate and signature record");
         }
@@ -185,32 +188,28 @@
 fn verify_signed_data(
     data: &Bytes,
     signature: &Signature,
-    key_info: &x509::SubjectPublicKeyInfo,
+    key_info: &SubjectPublicKeyInfo,
 ) -> Result<()> {
-    use ring::signature;
-    let verification_alg: &dyn signature::VerificationAlgorithm =
-        match signature.signature_algorithm_id {
-            SIGNATURE_RSA_PSS_WITH_SHA256 => &signature::RSA_PSS_2048_8192_SHA256,
-            SIGNATURE_RSA_PSS_WITH_SHA512 => &signature::RSA_PSS_2048_8192_SHA512,
-            SIGNATURE_RSA_PKCS1_V1_5_WITH_SHA256 | SIGNATURE_VERITY_RSA_PKCS1_V1_5_WITH_SHA256 => {
-                &signature::RSA_PKCS1_2048_8192_SHA256
-            }
-            SIGNATURE_RSA_PKCS1_V1_5_WITH_SHA512 => &signature::RSA_PKCS1_2048_8192_SHA512,
-            SIGNATURE_ECDSA_WITH_SHA256 | SIGNATURE_VERITY_ECDSA_WITH_SHA256 => {
-                &signature::ECDSA_P256_SHA256_ASN1
-            }
-            // TODO(b/190343842) not implemented signature algorithm
-            SIGNATURE_ECDSA_WITH_SHA512
-            | SIGNATURE_DSA_WITH_SHA256
-            | SIGNATURE_VERITY_DSA_WITH_SHA256 => {
-                bail!(
-                    "TODO(b/190343842) not implemented signature algorithm: {:#x}",
-                    signature.signature_algorithm_id
-                );
-            }
-            _ => bail!("Unsupported signature algorithm: {:#x}", signature.signature_algorithm_id),
-        };
-    let key = signature::UnparsedPublicKey::new(verification_alg, &key_info.subject_public_key);
+    let verification_alg: &dyn VerificationAlgorithm = match signature.signature_algorithm_id {
+        SIGNATURE_RSA_PSS_WITH_SHA256 => &RSA_PSS_2048_8192_SHA256,
+        SIGNATURE_RSA_PSS_WITH_SHA512 => &RSA_PSS_2048_8192_SHA512,
+        SIGNATURE_RSA_PKCS1_V1_5_WITH_SHA256 | SIGNATURE_VERITY_RSA_PKCS1_V1_5_WITH_SHA256 => {
+            &RSA_PKCS1_2048_8192_SHA256
+        }
+        SIGNATURE_RSA_PKCS1_V1_5_WITH_SHA512 => &RSA_PKCS1_2048_8192_SHA512,
+        SIGNATURE_ECDSA_WITH_SHA256 | SIGNATURE_VERITY_ECDSA_WITH_SHA256 => &ECDSA_P256_SHA256_ASN1,
+        // TODO(b/190343842) not implemented signature algorithm
+        SIGNATURE_ECDSA_WITH_SHA512
+        | SIGNATURE_DSA_WITH_SHA256
+        | SIGNATURE_VERITY_DSA_WITH_SHA256 => {
+            bail!(
+                "TODO(b/190343842) not implemented signature algorithm: {:#x}",
+                signature.signature_algorithm_id
+            );
+        }
+        _ => bail!("Unsupported signature algorithm: {:#x}", signature.signature_algorithm_id),
+    };
+    let key = UnparsedPublicKey::new(verification_alg, &key_info.subject_public_key);
     key.verify(data.as_ref(), signature.signature.as_ref())?;
     Ok(())
 }
diff --git a/apkverify/src/ziputil.rs b/apkverify/src/ziputil.rs
index bfb1c01..f18a38a 100644
--- a/apkverify/src/ziputil.rs
+++ b/apkverify/src/ziputil.rs
@@ -93,7 +93,7 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::assert_contains;
+    use crate::testing::assert_contains;
     use std::io::{Cursor, Write};
     use zip::{write::FileOptions, ZipWriter};
 
@@ -125,6 +125,6 @@
         // ZipArchive::new() succeeds, but we should reject
         let res = zip_sections(Cursor::new([pre_eocd, cd, eocd].concat()));
         assert!(res.is_err());
-        assert_contains!(res.err().unwrap().to_string(), "Invalid ZIP: offset should be 0");
+        assert_contains(&res.err().unwrap().to_string(), "Invalid ZIP: offset should be 0");
     }
 }
diff --git a/apkverify/tests/apkverify_test.rs b/apkverify/tests/apkverify_test.rs
index 3366524..ade4468 100644
--- a/apkverify/tests/apkverify_test.rs
+++ b/apkverify/tests/apkverify_test.rs
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-use apkverify::{assert_contains, verify};
+use apkverify::{testing::assert_contains, verify};
 use std::matches;
 
 #[test]
@@ -26,14 +26,14 @@
 fn test_verify_v3_digest_mismatch() {
     let res = verify("tests/data/v3-only-with-rsa-pkcs1-sha512-8192-digest-mismatch.apk");
     assert!(res.is_err());
-    assert_contains!(res.err().unwrap().to_string(), "Digest mismatch");
+    assert_contains(&res.unwrap_err().to_string(), "Digest mismatch");
 }
 
 #[test]
-fn test_verify_v3_cert_and_publick_key_mismatch() {
+fn test_verify_v3_cert_and_public_key_mismatch() {
     let res = verify("tests/data/v3-only-cert-and-public-key-mismatch.apk");
     assert!(res.is_err());
-    assert_contains!(res.err().unwrap().to_string(), "Public key mismatch");
+    assert_contains(&res.unwrap_err().to_string(), "Public key mismatch");
 }
 
 #[test]
@@ -42,7 +42,7 @@
     let res = verify("tests/data/v2-only-truncated-cd.apk");
     // TODO(jooyung): consider making a helper for err assertion
     assert!(matches!(
-        res.err().unwrap().root_cause().downcast_ref::<ZipError>().unwrap(),
+        res.unwrap_err().root_cause().downcast_ref::<ZipError>().unwrap(),
         ZipError::InvalidArchive(_),
     ));
 }
diff --git a/idsig/src/apksigv4.rs b/idsig/src/apksigv4.rs
index 6f4603d..5f4e92a 100644
--- a/idsig/src/apksigv4.rs
+++ b/idsig/src/apksigv4.rs
@@ -183,7 +183,7 @@
 
 #[cfg(test)]
 mod tests {
-    use crate::apksigv4::*;
+    use super::*;
     use std::io::Cursor;
 
     fn hexstring_from(s: &[u8]) -> String {
diff --git a/idsig/src/hashtree.rs b/idsig/src/hashtree.rs
index a4727a9..b91698b 100644
--- a/idsig/src/hashtree.rs
+++ b/idsig/src/hashtree.rs
@@ -191,7 +191,7 @@
 
 #[cfg(test)]
 mod tests {
-    use crate::hashtree::*;
+    use super::*;
     use ring::digest;
     use std::fs::{self, File};