Repository: cobalt-org/liquid-rust (rust)

Issue:
Integration tests are not run
The tests in the `tests` folder are not run.

Because of the `[[test]]` in `Cargo.toml` cargo only run the test specified here. And this test is just an empty file. Because you want to use a non-default feature in a test, this means you cannot just remove this section.

I see multiple ways to solve this issue:

1. Manually specify all the tests in `Cargo.toml`
2. Include all other tests from `liquid.rs` (via `mod`) (this could be done automatically with code generation in `build.rs`)
3. Remove the section from `Cargo.toml` but specify the feature on the command line each time (`cargo test --features "serde"`)

Pull request description:
feat: Turn `serde` into a default feature.
This is actually more of a workaround that I don't mind.  There isn't a
low maintenance way to enable a feature for tests.  I misunderstood
cargo's documentation and thought I could add a `[[test]]` section but
that instead disabled all the tests.

Fixes #128

Patch:
diff --git a/.travis.yml b/.travis.yml
index 1fe9127..4cb72f6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,11 +17,11 @@ script:
   - cargo -V
   - cargo check --verbose
   - cargo check --verbose --features "cli"
-  - cargo check --verbose --features "cli serde serde_yaml serde_json"
-  - cargo test  --verbose --features "cli serde serde_yaml serde_json"
+  - cargo check --verbose --features "cli serde_yaml serde_json"
+  - cargo test  --verbose --features "cli serde_yaml serde_json"
   - ! which cargo-clippy || cargo when --channel nightly clippy -- --version
-  - ! which cargo-clippy || cargo when --channel nightly clippy --features "cli serde serde_yaml serde_json"
-  - cargo when --channel nightly bench --features "cli serde serde_yaml serde_json"
+  - ! which cargo-clippy || cargo when --channel nightly clippy --features "cli serde_yaml serde_json"
+  - cargo when --channel nightly bench --features "cli serde_yaml serde_json"
   - cargo when --channel stable doc --no-deps --all-features
   - cargo when --channel stable fmt -- --version
   - cargo when --channel stable fmt -- --write-mode=diff
diff --git a/Cargo.toml b/Cargo.toml
index d6a6751..3d4a918 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,12 +24,8 @@ doctest = false
 bench = false
 doc = false
 
-[[test]]
-name = "liquid"
-required-features = ["serde"]
-
 [features]
-default = ["extra-filters"]
+default = ["extra-filters", "serde"]
 cli = ["clap", "error-chain", "serde_yaml"]
 extra-filters = []
 dev = []
@@ -50,6 +46,7 @@ serde_json = { version = "1.0", optional = true }
 
 [build-dependencies]
 skeptic = "0.9"
+serde = { version = "1.0", features = ["derive"] }
 
 [dev-dependencies]
 difference = "1.0"


Test patch:
diff --git a/tests/liquid.rs b/tests/liquid.rs
deleted file mode 100644
index 8b13789..0000000
--- a/tests/liquid.rs
+++ /dev/null
@@ -1,1 +0,0 @@
-