Move is_installed() to ark_test

It runs R code, so is very R specific

Author: DavisVaughan

crates/amalthea/src/fixtures/dummy_frontend.rs

@@ -606,31 +606,6 @@ impl DummyFrontend {
             (data.content.comm_id, data.content.target_name, data.content.data)
         })
     }
-
-    pub fn is_installed(&self, package: &str) -> bool {
-        let code = format!(".ps.is_installed('{package}')");
-        self.send_execute_request(&code, ExecuteRequestOptions::default());
-        self.recv_iopub_busy();
-
-        let input = self.recv_iopub_execute_input();
-        assert_eq!(input.code, code);
-
-        let result = self.recv_iopub_execute_result();
-
-        let out = if result == "[1] TRUE" {
-            true
-        } else if result == "[1] FALSE" {
-            false
-        } else {
-            panic!("Expected `TRUE` or `FALSE`, got '{result}'.");
-        };
-
-        self.recv_iopub_idle();
-
-        assert_eq!(self.recv_shell_execute_reply(), input.execution_count);
-
-        out
-    }
 }
 
 impl Default for ExecuteRequestOptions {

crates/ark_test/src/dummy_frontend.rs

@@ -1335,6 +1335,31 @@ impl DummyArkFrontend {
             Some(content.to_string())
         }
     }
+
+    pub fn is_installed(&self, package: &str) -> bool {
+        let code = format!(".ps.is_installed('{package}')");
+        self.send_execute_request(&code, ExecuteRequestOptions::default());
+        self.recv_iopub_busy();
+
+        let input = self.recv_iopub_execute_input();
+        assert_eq!(input.code, code);
+
+        let result = self.recv_iopub_execute_result();
+
+        let out = if result == "[1] TRUE" {
+            true
+        } else if result == "[1] FALSE" {
+            false
+        } else {
+            panic!("Expected `TRUE` or `FALSE`, got '{result}'.");
+        };
+
+        self.recv_iopub_idle();
+
+        assert_eq!(self.recv_shell_execute_reply(), input.execution_count);
+
+        out
+    }
 }
 
 /// Result of sourcing a file via `send_source()`.