[gnome-calculator/60-split-out-a-backend-library] gcalc: implemented group solving on constants

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 9d4c2360330f4e08b99a1e00df036d58aa676a0b
Author: Daniel Espinosa Ortiz <esodan gmail com>
Date:   Fri Jan 4 12:28:21 2019 -0600

    gcalc: implemented group solving on constants

 gcalc/gcalc-group.vala         | 19 ++++++++++--
 tests/gcalc-solving-basic.vala | 69 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 2 deletions(-)
---
diff --git a/gcalc/gcalc-group.vala b/gcalc/gcalc-group.vala
index c56c98b8..cfe4c994 100644
--- a/gcalc/gcalc-group.vala
+++ b/gcalc/gcalc-group.vala
@@ -19,12 +19,27 @@
  *      Daniel Espinosa <esodan gmail com>
  */
 public interface GCalc.Group : Object, Expression {
-  public abstract Level level { get; set; }
-  public abstract bool closed { get; set; }
   public enum Level {
     ONE,
     TWO,
     THREE
   }
+  public abstract Level level { get; set; }
+  public abstract bool closed { get; set; }
+  public virtual Expression evaluate () throws GLib.Error {
+    if (expressions.get_n_items () == 0) {
+      throw new GroupError.INVALID_POLYNOMIAL ("No internal polynomial in group");
+    }
+    var e = expressions.get_item (0) as Polynomial;
+    if (e == null) {
+      throw new GroupError.INVALID_POLYNOMIAL ("Invalid internal polynomial in group");
+    }
+    return e.evaluate ();
+  }
+}
+
+public errordomain GCalc.GroupError {
+  INVALID_POLYNOMIAL,
+  INVALID_INTERNAL_TERM,
 }
 
diff --git a/tests/gcalc-solving-basic.vala b/tests/gcalc-solving-basic.vala
index 85ab7f14..a8e38410 100644
--- a/tests/gcalc-solving-basic.vala
+++ b/tests/gcalc-solving-basic.vala
@@ -245,6 +245,75 @@ class Tests {
         warning ("Error: %s", e.message);
       }
     });
+    Test.add_func ("/gcalc/solve/group/constant",
+    ()=>{
+      try {
+        var parser = new Parser ();
+        var eqman = new GMathEquationManager ();
+        parser.parse ("(1)", eqman);
+        assert (eqman.equations.get_n_items () == 1);
+        var eq = eqman.equations.get_item (0) as MathEquation;
+        assert (eq != null);
+        var e = eq.expressions.get_item (0) as Polynomial;
+        assert (e != null);
+        var t = e.expressions.get_item (0) as Term;
+        assert (t != null);
+        var g = t.expressions.get_item (0) as Group;
+        assert (g != null);
+        var res = g.evaluate () as Constant;
+        assert (res != null);
+        message ("Constant Result: %s", res.to_string ());
+        assert (res.real () == 1.0);
+      } catch (GLib.Error e) {
+        warning ("Error: %s", e.message);
+      }
+    });
+    Test.add_func ("/gcalc/solve/group/constant/basic-polynomial",
+    ()=>{
+      try {
+        var parser = new Parser ();
+        var eqman = new GMathEquationManager ();
+        parser.parse ("(1+2)", eqman);
+        assert (eqman.equations.get_n_items () == 1);
+        var eq = eqman.equations.get_item (0) as MathEquation;
+        assert (eq != null);
+        var e = eq.expressions.get_item (0) as Polynomial;
+        assert (e != null);
+        var t = e.expressions.get_item (0) as Term;
+        assert (t != null);
+        var g = t.expressions.get_item (0) as Group;
+        assert (g != null);
+        var res = g.evaluate () as Constant;
+        assert (res != null);
+        message ("Constant Result: %s", res.to_string ());
+        assert (res.real () == 3.0);
+      } catch (GLib.Error e) {
+        warning ("Error: %s", e.message);
+      }
+    });
+    Test.add_func ("/gcalc/solve/group/constant/polynomial",
+    ()=>{
+      try {
+        var parser = new Parser ();
+        var eqman = new GMathEquationManager ();
+        parser.parse ("(2*8-10/5)", eqman);
+        assert (eqman.equations.get_n_items () == 1);
+        var eq = eqman.equations.get_item (0) as MathEquation;
+        assert (eq != null);
+        var e = eq.expressions.get_item (0) as Polynomial;
+        assert (e != null);
+        var t = e.expressions.get_item (0) as Term;
+        assert (t != null);
+        var g = t.expressions.get_item (0) as Group;
+        assert (g != null);
+        var res = g.evaluate () as Constant;
+        assert (res != null);
+        message ("Constant Result: %s", res.to_string ());
+        assert (res.real () == 14.0);
+      } catch (GLib.Error e) {
+        warning ("Error: %s", e.message);
+      }
+    });
     return Test.run ();
   }
 }