add comments documenting cram is used for jose-util testing

Cherry-picked from #274

.gitignore

@@ -5,3 +5,4 @@
 *.pem
 *.cov
 jose-util/jose-util
+jose-util.t.err

.travis.yml

@@ -35,10 +35,9 @@ script:
 - go test ./cipher -v -covermode=count -coverprofile=cipher/profile.cov
 - go test ./jwt -v -covermode=count -coverprofile=jwt/profile.cov
 - go test ./json -v # no coverage for forked encoding/json package
-- cd jose-util && go build && PATH=$PWD:$PATH cram -v jose-util.t
+- cd jose-util && go build && PATH=$PWD:$PATH cram -v jose-util.t # cram tests jose-util
 - cd ..
 
 after_success:
 - gocovmerge *.cov */*.cov > merged.coverprofile
 - $HOME/gopath/bin/goveralls -coverprofile merged.coverprofile -service=travis-ci
-

jose-util/README.md

@@ -25,6 +25,14 @@ Keys are specified via the `--key` flag. Supported key types are naked RSA/EC
 keys and X.509 certificates with embedded RSA/EC keys. Keys must be in PEM
 or DER formats.
 
+
+## Testing
+
+`cram` is used for testing.  This can be installed with pip or `sudo apt install
+python-cram` See the travis file for how this is used in testing. For example,
+`go build && PATH=$PWD:$PATH cram -v jose-util.t`
+
+
 ## Examples
 
 ### Encrypt

jose-util/jose-util.t

@@ -1,4 +1,7 @@
-Set up test keys.
+This is a cram test file.  See the travis file for how this is used in testing.
+For example, `go build && PATH=$PWD:$PATH cram -v jose-util.t`
+
+Set up static test keys.
 
   $ cat > rsa.pub <<EOF
   > -----BEGIN PUBLIC KEY-----
@@ -61,28 +64,28 @@ Set up test keys.
 
 Encrypt and then decrypt a test message (RSA).
 
-  $ echo "Lorem ipsum dolor sit amet" | 
+  $ echo "Lorem ipsum dolor sit amet" |
   > jose-util encrypt --alg RSA-OAEP --enc A128GCM --key rsa.pub |
   > jose-util decrypt --key rsa.key
   Lorem ipsum dolor sit amet
 
 Encrypt and then decrypt a test message (EC).
 
-  $ echo "Lorem ipsum dolor sit amet" | 
+  $ echo "Lorem ipsum dolor sit amet" |
   > jose-util encrypt --alg ECDH-ES+A128KW --enc A128GCM --key ec.pub |
   > jose-util decrypt --key ec.key
   Lorem ipsum dolor sit amet
 
 Sign and verify a test message (RSA).
 
-  $ echo "Lorem ipsum dolor sit amet" | 
+  $ echo "Lorem ipsum dolor sit amet" |
   > jose-util sign --alg PS256 --key rsa.key |
   > jose-util verify --key rsa.pub
   Lorem ipsum dolor sit amet
 
 Sign and verify a test message (EC).
 
-  $ echo "Lorem ipsum dolor sit amet" | 
+  $ echo "Lorem ipsum dolor sit amet" |
   > jose-util sign --alg ES384 --key ec.key |
   > jose-util verify --key ec.pub
   Lorem ipsum dolor sit amet