Note test dependencies in README

Closes egraphs-good#175

Author: mwillsey

.github/workflows/build.yml

@@ -11,8 +11,8 @@ jobs:
       with:
         path: ~/.cargo/bin
         key: ${{ runner.os }}-cargo-bin
-    - name: Install graphviz and cbc
-      run: sudo apt-get install graphviz coinor-libcbc-dev 
+    - name: Install cbc
+      run: sudo apt-get install coinor-libcbc-dev 
     - name: Test
       run: make test
   nits:

README.md

@@ -49,11 +49,13 @@ Typically, you install Rust using [`rustup`](https://www.rust-lang.org/tools/ins
 
 Run `cargo doc --open` to build and open the documentation in a browser.
 
-Before committing/pushing, make sure to run `make`, which runs all the tests and lints that CI will.
+Before committing/pushing, make sure to run `make`, 
+ which runs all the tests and lints that CI will (including those under feature flags).
+This requires the [`cbc`](https://projects.coin-or.org/Cbc) solver
+ due to the `lp` feature.
 
 ### Tests
 
-You will need [`graphviz`](https://www.graphviz.org/download/) to run the tests.
 Running `cargo test` will run the tests.
 Some tests may time out; try `cargo test --release` if that happens.
 

src/dot.rs

@@ -21,7 +21,7 @@ The [`EGraph::dot`](EGraph::dot()) method creates `Dot`s.
 
 # Example
 
-```
+```no_run
 use egg::{*, rewrite as rw};
 
 let rules = &[
@@ -38,9 +38,9 @@ println!("My egraph dot file: {}", egraph.dot());
 
 // create a Dot and then compile it assuming `dot` is on the system
 egraph.dot().to_svg("target/foo.svg").unwrap();
-// egraph.dot().to_png("target/foo.png").unwrap();
-// egraph.dot().to_pdf("target/foo.pdf").unwrap();
-// egraph.dot().to_dot("target/foo.dot").unwrap();
+egraph.dot().to_png("target/foo.png").unwrap();
+egraph.dot().to_pdf("target/foo.pdf").unwrap();
+egraph.dot().to_dot("target/foo.dot").unwrap();
 ```
 
 Note that self-edges (from an enode to its containing eclass) will be

src/egraph.rs

@@ -953,8 +953,6 @@ mod tests {
             "union x and y".to_string(),
         );
         egraph.rebuild();
-
-        egraph.dot().to_dot("target/foo.dot").unwrap();
     }
 
     #[cfg(all(feature = "serde-1", feature = "serde_json"))]