feat: support additional ganache arguments (#347)

* feat: support additional ganache arguments

* feat: add fork argument option

ethers-core/src/utils/ganache.rs

@@ -81,6 +81,8 @@ pub struct Ganache {
     port: Option<u16>,
     block_time: Option<u64>,
     mnemonic: Option<String>,
+    fork: Option<String>,
+    args: Vec<String>,
 }
 
 impl Ganache {
@@ -108,6 +110,33 @@ impl Ganache {
         self
     }
 
+    /// Sets the `fork` argument to fork from another currently running Ethereum client
+    /// at a given block. Input should be the HTTP location and port of the other client,
+    /// e.g. `http://localhost:8545`. You can optionally specify the block to fork from
+    /// using an @ sign: `http://localhost:8545@1599200`
+    pub fn fork<T: Into<String>>(mut self, fork: T) -> Self {
+        self.fork = Some(fork.into());
+        self
+    }
+
+    /// Adds an argument to pass to the `ganache-cli`.
+    pub fn arg<T: Into<String>>(mut self, arg: T) -> Self {
+        self.args.push(arg.into());
+        self
+    }
+
+    /// Adds multiple arguments to pass to the `ganache-cli`.
+    pub fn args<I, S>(mut self, args: I) -> Self
+    where
+        I: IntoIterator<Item = S>,
+        S: Into<String>,
+    {
+        for arg in args {
+            self = self.arg(arg);
+        }
+        self
+    }
+
     /// Consumes the builder and spawns `ganache-cli` with stdout redirected
     /// to /dev/null. This takes ~2 seconds to execute as it blocks while
     /// waiting for `ganache-cli` to launch.
@@ -129,6 +158,12 @@ impl Ganache {
             cmd.arg("-b").arg(block_time.to_string());
         }
 
+        if let Some(fork) = self.fork {
+            cmd.arg("-f").arg(fork);
+        }
+
+        cmd.args(self.args);
+
         let mut child = cmd.spawn().expect("couldnt start ganache-cli");
 
         let stdout = child