Test harness for HyphaeVM

This commit adds a testing framework for HyphaeVM which enables
testing various aspects of the VM state after running input programs
against a VM with possibly preinitialized state.

This includes a builder pattern initializer for the VM, and bespoke
logic for a test case tester.

Signed-off-by: Ava Affine <ava@sunnypup.io>

hyphae/src/vm.rs

@@ -25,6 +25,7 @@ use crate::util::{Operand, Program, Address};
 use crate::heap::{Gc, Datum, Cons};
 
 use core::ops::DerefMut;
+use core::array;
 
 use alloc::vec;
 use alloc::vec::Vec;
@@ -36,12 +37,12 @@ use num::pow::Pow;
 
 const NUM_OPERAND_REGISTERS: usize = 4;
 
+#[derive(Clone)]
 pub struct VM {
     // execution environment
     pub stack:  StackStack<Gc<Datum>>,
     pub symtab: QuickMap<Operand>,
     pub prog:   Program,
-    pub fds:    Vec<u64>,
     pub traps:  Vec<Arc<dyn Fn(&mut VM)>>,
 
     // data registers
@@ -58,7 +59,71 @@ pub struct VM {
     pub err_state: bool,
 }
 
+impl From<Program> for VM {
+    fn from(value: Program) -> Self {
+        VM{
+            stack: StackStack::new(),
+            symtab: QuickMap::new(),
+            prog: value,
+            traps: vec![],
+            expr: Datum::None.into(),
+            oper: array::from_fn(|_| Datum::None.into()),
+            retn: 0,
+            ictr: 0,
+            errr: Datum::None.into(),
+            running: true,
+            err_state: false
+        }
+    }
+}
+
 impl VM {
+    pub fn new_with_opts(
+        program: Program,
+        traps: Option<Vec<Arc<dyn Fn(&mut VM)>>>,
+        stack: Option<StackStack<Gc<Datum>>>,
+        syms:  Option<QuickMap<Operand>>
+    ) -> VM {
+        Into::<VM>::into(program)
+            .with_stack(stack)
+            .with_symbols(syms)
+            .with_traps(traps)
+            .to_owned() // not efficient, but we are not executing
+    }
+
+    pub fn with_stack(
+        &mut self,
+        maybe_stack: Option<StackStack<Gc<Datum>>>,
+    ) -> &mut VM {
+        if let Some(stack) = maybe_stack {
+            self.stack = stack;
+        }
+
+        self
+    }
+
+    pub fn with_symbols(
+        &mut self,
+        maybe_symbols: Option<QuickMap<Operand>>,
+    ) -> &mut VM {
+        if let Some(symbols) = maybe_symbols {
+            self.symtab = symbols;
+        }
+
+        self
+    }
+
+    pub fn with_traps(
+        &mut self,
+        maybe_traps: Option<Vec<Arc<dyn Fn(&mut VM)>>>,
+    ) -> &mut VM {
+        if let Some(traps) = maybe_traps {
+            self.traps = traps;
+        }
+
+        self
+    }
+
     pub fn run_program(&mut self) {
         if self.prog.0.len() < 1 {
             self.running = false;
@@ -521,3 +586,196 @@ impl VM {
     }
 }
 
+#[cfg(test)]
+mod tests {
+    use core::array;
+    use super::*;
+    use crate::instr;
+
+    const ISA_TESTS: [Option<Vec<(VM, TestResult)>>; instr::TOTAL_INSTRUCTIONS] = [
+        // TRAP
+        None,
+        // BIND
+        None,
+        // UNBIND
+        None,
+        // BOUND
+        None,
+        // PUSH
+        None,
+        // POP
+        None,
+        // ENTER
+        None,
+        // EXIT
+        None,
+        // LOAD
+        None,
+        // DUPL
+        None,
+        // CLEAR
+        None,
+        // NOP
+        None,
+        // HALT
+        None,
+        // PANIC
+        None,
+        // JMP
+        None,
+        // JMPIF
+        None,
+        // EQ
+        None,
+        // LT
+        None,
+        // GT
+        None,
+        // LTE
+        None,
+        // GTE
+        None,
+        // BOOL_NOT
+        None,
+        // BOOL_AND
+        None,
+        // BOOL_OR
+        None,
+        // BYTE_AND
+        None,
+        // BYTE_OR
+        None,
+        // XOR
+        None,
+        // BYTE_NOT
+        None,
+        // ADD
+        None,
+        // SUB
+        None,
+        // MUL
+        None,
+        // FDIV
+        None,
+        // IDIV
+        None,
+        // POW
+        None,
+        // MODULO
+        None,
+        // REM
+        None,
+        // INC
+        None,
+        // DEC
+        None,
+        // CTON
+        None,
+        // NTOC
+        None,
+        // NTOI
+        None,
+        // NTOE
+        None,
+        // CONST
+        None,
+        // MKVEC
+        None,
+        // MKBVEC
+        None,
+        // INDEX
+        None,
+        // LENGTH
+        None,
+        // SUBSL
+        None,
+        // INSER
+        None,
+        // CONS
+        None,
+        // CAR
+        None,
+        // CDR
+        None,
+        // CONCAT
+        None,
+        // S_APPEND
+        None,
+    ];
+
+    fn has_stack(state: &VM, idx: usize, target: Gc<Datum>) -> bool {
+        *(state.stack[idx]) == *target
+    }
+
+    fn has_sym(state: &VM, sym: &str, operand: Option<Operand>) -> bool {
+        (operand.is_some() == state.symtab.contains_key(sym)) &&
+            (operand.is_none() || state.symtab.get(&sym.to_owned()) == 
+                operand.as_ref())
+    }
+
+    #[derive(Clone)]
+    struct TestResult {
+        expr: Option<Gc<Datum>>,
+        stack: Vec<(usize, Gc<Datum>)>,
+        syms: Vec<(&'static str, Option<Operand>)>,
+        errr: Option<&'static str>
+    }
+
+    impl TestResult {
+        fn chk_expr(&self, state: &VM) -> bool {
+            self.expr.is_none() || *(state.expr) == *(self.expr.clone().unwrap())
+        }
+
+        fn chk_err(&self, state: &VM) -> bool {
+            if let Datum::String(ref msg) = *state.errr {
+                let msg = unsafe { str::from_utf8_unchecked(msg) };
+                msg == self.errr.unwrap()
+            } else if let Datum::None = *state.errr {
+                self.errr.is_none()
+            } else {
+                false
+            }
+        }
+
+        fn chk_stack(&self, state: &VM) -> bool {
+            for i in &self.stack {
+                if !has_stack(&state, i.0, i.1.clone()) {
+                    return false
+                }
+            }
+            true
+        }
+
+        fn chk_syms(&self, state: &VM) -> bool {
+            for i in &self.syms {
+                if !has_sym(&state, i.0, i.1.clone()) {
+                    return false
+                }
+            }
+            true
+        }
+
+        fn test_passes(&self, state: VM) -> bool {
+            (self.expr.is_none()   || self.chk_expr(&state))  &&
+            (self.stack.is_empty() || self.chk_stack(&state)) &&
+            (self.syms.is_empty()  || self.chk_syms(&state))  &&
+            (self.errr.is_none()   || self.chk_err(&state))
+        }
+    }
+
+    #[test]
+    fn run_isa_tests() {
+        for i in &ISA_TESTS.to_vec() {
+            let Some(test_case) = i else {
+                assert!(false); // dont let untested instructions happen
+                return
+            };
+
+            for i in test_case {
+                let (mut vm, result) = (i.0.clone(), i.1.clone());
+                vm.run_program();
+                assert!(result.test_passes(vm));
+            }
+        }
+    }
+}